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* Merge tag 'locking-urgent-2021-11-14' of ↵Linus Torvalds2021-11-142-4/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 static call update from Thomas Gleixner: "A single fix for static calls to make the trampoline patching more robust by placing explicit signature bytes after the call trampoline to prevent patching random other jumps like the CFI jump table entries" * tag 'locking-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: static_call,x86: Robustify trampoline patching
| * static_call,x86: Robustify trampoline patchingPeter Zijlstra2021-11-112-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a few signature bytes after the static call trampoline and verify those bytes match before patching the trampoline. This avoids patching random other JMPs (such as CFI jump-table entries) instead. These bytes decode as: d: 53 push %rbx e: 43 54 rex.XB push %r12 And happen to spell "SCT". Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211030074758.GT174703@worktop.programming.kicks-ass.net
* | Merge tag 'sched_urgent_for_v5.16_rc1' of ↵Linus Torvalds2021-11-143-16/+15
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Borislav Petkov: - Avoid touching ~100 config files in order to be able to select the preemption model - clear cluster CPU masks too, on the CPU unplug path - prevent use-after-free in cfs - Prevent a race condition when updating CPU cache domains - Factor out common shared part of smp_prepare_cpus() into a common helper which can be called by both baremetal and Xen, in order to fix a booting of Xen PV guests * tag 'sched_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: preempt: Restore preemption model selection configs arch_topology: Fix missing clear cluster_cpumask in remove_cpu_topology() sched/fair: Prevent dead task groups from regaining cfs_rq's sched/core: Mitigate race cpus_share_cache()/update_top_cache_domain() x86/smp: Factor out parts of native_smp_prepare_cpus()
| * | x86/smp: Factor out parts of native_smp_prepare_cpus()Boris Ostrovsky2021-11-113-16/+15
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 66558b730f25 ("sched: Add cluster scheduler level for x86") introduced cpu_l2c_shared_map mask which is expected to be initialized by smp_op.smp_prepare_cpus(). That commit only updated native_smp_prepare_cpus() version but not xen_pv_smp_prepare_cpus(). As result Xen PV guests crash in set_cpu_sibling_map(). While the new mask can be allocated in xen_pv_smp_prepare_cpus() one can see that both versions of smp_prepare_cpus ops share a number of common operations that can be factored out. So do that instead. Fixes: 66558b730f25 ("sched: Add cluster scheduler level for x86") Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lkml.kernel.org/r/1635896196-18961-1-git-send-email-boris.ostrovsky@oracle.com
* | Merge tag 'perf_urgent_for_v5.16_rc1' of ↵Linus Torvalds2021-11-142-1/+5
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Borislav Petkov: - Prevent unintentional page sharing by checking whether a page reference to a PMU samples page has been acquired properly before that - Make sure the LBR_SELECT MSR is saved/restored too - Reset the LBR_SELECT MSR when resetting the LBR PMU to clear any residual data left * tag 'perf_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: Avoid put_page() when GUP fails perf/x86/vlbr: Add c->flags to vlbr event constraints perf/x86/lbr: Reset LBR_SELECT during vlbr reset
| * | perf/x86/vlbr: Add c->flags to vlbr event constraintsLike Xu2021-11-111-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Just like what we do in the x86_get_event_constraints(), the PERF_X86_EVENT_LBR_SELECT flag should also be propagated to event->hw.flags so that the host lbr driver can save/restore MSR_LBR_SELECT for the special vlbr event created by KVM or BPF. Fixes: 097e4311cda9 ("perf/x86: Add constraint to create guest LBR event without hw counter") Reported-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Like Xu <likexu@tencent.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Wanpeng Li <wanpengli@tencent.com> Link: https://lore.kernel.org/r/20211103091716.59906-1-likexu@tencent.com
| * | perf/x86/lbr: Reset LBR_SELECT during vlbr resetWanpeng Li2021-11-111-0/+2
| |/ | | | | | | | | | | | | | | | | | | lbr_select in kvm guest has residual data even if kvm guest is poweroff. We can get residual data in the next boot. Because lbr_select is not reset during kvm vlbr release. Let's reset LBR_SELECT during vlbr reset. Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/1636096851-36623-1-git-send-email-wanpengli@tencent.com
* | Merge tag 'x86_urgent_for_v5.16_rc1' of ↵Linus Torvalds2021-11-146-4/+60
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Borislav Petkov: - Add the model number of a new, Raptor Lake CPU, to intel-family.h - Do not log spurious corrected MCEs on SKL too, due to an erratum - Clarify the path of paravirt ops patches upstream - Add an optimization to avoid writing out AMX components to sigframes when former are in init state * tag 'x86_urgent_for_v5.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu: Add Raptor Lake to Intel family x86/mce: Add errata workaround for Skylake SKX37 MAINTAINERS: Add some information to PARAVIRT_OPS entry x86/fpu: Optimize out sigframe xfeatures when in init state
| * | x86/cpu: Add Raptor Lake to Intel familyTony Luck2021-11-121-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add model ID for Raptor Lake. [ dhansen: These get added as soon as possible so that folks doing development can leverage them. ] Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lkml.kernel.org/r/20211112182835.924977-1-tony.luck@intel.com
| * | x86/mce: Add errata workaround for Skylake SKX37Dave Jones2021-11-121-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Errata SKX37 is word-for-word identical to the other errata listed in this workaround. I happened to notice this after investigating a CMCI storm on a Skylake host. While I can't confirm this was the root cause, spurious corrected errors does sound like a likely suspect. Fixes: 2976908e4198 ("x86/mce: Do not log spurious corrected mce errors") Signed-off-by: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20211029205759.GA7385@codemonkey.org.uk
| * | x86/fpu: Optimize out sigframe xfeatures when in init stateDave Hansen2021-11-034-2/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tl;dr: AMX state is ~8k. Signal frames can have space for this ~8k and each signal entry writes out all 8k even if it is zeros. Skip writing zeros for AMX to speed up signal delivery by about 4% overall when AMX is in its init state. This is a user-visible change to the sigframe ABI. == Hardware XSAVE Background == XSAVE state components may be tracked by the processor as being in their initial configuration. Software can detect which features are in this configuration by looking at the XSTATE_BV field in an XSAVE buffer or with the XGETBV(1) instruction. Both the XSAVE and XSAVEOPT instructions enumerate features s being in the initial configuration via the XSTATE_BV field in the XSAVE header, However, XSAVEOPT declines to actually write features in their initial configuration to the buffer. XSAVE writes the feature unconditionally, regardless of whether it is in the initial configuration or not. Basically, XSAVE users never need to inspect XSTATE_BV to determine if the feature has been written to the buffer. XSAVEOPT users *do* need to inspect XSTATE_BV. They might also need to clear out the buffer if they want to make an isolated change to the state, like modifying one register. == Software Signal / XSAVE Background == Signal frames have historically been written with XSAVE itself. Each state is written in its entirety, regardless of being in its initial configuration. In other words, the signal frame ABI uses the XSAVE behavior, not the XSAVEOPT behavior. == Problem == This means that any application which has acquired permission to use AMX via ARCH_REQ_XCOMP_PERM will write 8k of state to the signal frame. This 8k write will occur even when AMX was in its initial configuration and software *knows* this because of XSTATE_BV. This problem also exists to a lesser degree with AVX-512 and its 2k of state. However, AVX-512 use does not require ARCH_REQ_XCOMP_PERM and is more likely to have existing users which would be impacted by any change in behavior. == Solution == Stop writing out AMX xfeatures which are in their initial state to the signal frame. This effectively makes the signal frame XSAVE buffer look as if it were written with a combination of XSAVEOPT and XSAVE behavior. Userspace which handles XSAVEOPT- style buffers should be able to handle this naturally. For now, include only the AMX xfeatures: XTILE and XTILEDATA in this new behavior. These require new ABI to use anyway, which makes their users very unlikely to be broken. This XSAVEOPT-like behavior should be expected for all future dynamic xfeatures. It may also be extended to legacy features like AVX-512 in the future. Only attempt this optimization on systems with dynamic features. Disable dynamic feature support (XFD) if XGETBV1 is unavailable by adding a CPUID dependency. This has been measured to reduce the *overall* cycle cost of signal delivery by about 4%. Fixes: 2308ee57d93d ("x86/fpu/amx: Enable the AMX feature in 64-bit mode") Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "Chang S. Bae" <chang.seok.bae@intel.com> Link: https://lore.kernel.org/r/20211102224750.FA412E26@davehans-spike.ostc.intel.com
* | | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2021-11-1330-336/+803
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull more kvm updates from Paolo Bonzini: "New x86 features: - Guest API and guest kernel support for SEV live migration - SEV and SEV-ES intra-host migration Bugfixes and cleanups for x86: - Fix misuse of gfn-to-pfn cache when recording guest steal time / preempted status - Fix selftests on APICv machines - Fix sparse warnings - Fix detection of KVM features in CPUID - Cleanups for bogus writes to MSR_KVM_PV_EOI_EN - Fixes and cleanups for MSR bitmap handling - Cleanups for INVPCID - Make x86 KVM_SOFT_MAX_VCPUS consistent with other architectures Bugfixes for ARM: - Fix finalization of host stage2 mappings - Tighten the return value of kvm_vcpu_preferred_target() - Make sure the extraction of ESR_ELx.EC is limited to architected bits" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (34 commits) KVM: SEV: unify cgroup cleanup code for svm_vm_migrate_from KVM: x86: move guest_pv_has out of user_access section KVM: x86: Drop arbitrary KVM_SOFT_MAX_VCPUS KVM: Move INVPCID type check from vmx and svm to the common kvm_handle_invpcid() KVM: VMX: Add a helper function to retrieve the GPR index for INVPCID, INVVPID, and INVEPT KVM: nVMX: Clean up x2APIC MSR handling for L2 KVM: VMX: Macrofy the MSR bitmap getters and setters KVM: nVMX: Handle dynamic MSR intercept toggling KVM: nVMX: Query current VMCS when determining if MSR bitmaps are in use KVM: x86: Don't update vcpu->arch.pv_eoi.msr_val when a bogus value was written to MSR_KVM_PV_EOI_EN KVM: x86: Rename kvm_lapic_enable_pv_eoi() KVM: x86: Make sure KVM_CPUID_FEATURES really are KVM_CPUID_FEATURES KVM: x86: Add helper to consolidate core logic of SET_CPUID{2} flows kvm: mmu: Use fast PF path for access tracking of huge pages when possible KVM: x86/mmu: Properly dereference rcu-protected TDP MMU sptep iterator KVM: x86: inhibit APICv when KVM_GUESTDBG_BLOCKIRQ active kvm: x86: Convert return type of *is_valid_rdpmc_ecx() to bool KVM: x86: Fix recording of guest steal time / preempted status selftest: KVM: Add intra host migration tests selftest: KVM: Add open sev dev helper ...
| * | | KVM: SEV: unify cgroup cleanup code for svm_vm_migrate_fromPaolo Bonzini2021-11-121-14/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the same cleanup code independent of whether the cgroup to be uncharged and unref'd is the source or the destination cgroup. Use a bool to track whether the destination cgroup has been charged, which also fixes a bug in the error case: the destination cgroup must be uncharged only if it does not match the source. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | KVM: x86: move guest_pv_has out of user_access sectionPaolo Bonzini2021-11-121-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When UBSAN is enabled, the code emitted for the call to guest_pv_has includes a call to __ubsan_handle_load_invalid_value. objtool complains that this call happens with UACCESS enabled; to avoid the warning, pull the calls to user_access_begin into both arms of the "if" statement, after the check for guest_pv_has. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | Merge branch 'kvm-5.16-fixes' into kvm-masterPaolo Bonzini2021-11-1120-264/+317
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Fix misuse of gfn-to-pfn cache when recording guest steal time / preempted status * Fix selftests on APICv machines * Fix sparse warnings * Fix detection of KVM features in CPUID * Cleanups for bogus writes to MSR_KVM_PV_EOI_EN * Fixes and cleanups for MSR bitmap handling * Cleanups for INVPCID * Make x86 KVM_SOFT_MAX_VCPUS consistent with other architectures
| | * | | KVM: x86: Drop arbitrary KVM_SOFT_MAX_VCPUSVitaly Kuznetsov2021-11-112-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM_CAP_NR_VCPUS is used to get the "recommended" maximum number of VCPUs and arm64/mips/riscv report num_online_cpus(). Powerpc reports either num_online_cpus() or num_present_cpus(), s390 has multiple constants depending on hardware features. On x86, KVM reports an arbitrary value of '710' which is supposed to be the maximum tested value but it's possible to test all KVM_MAX_VCPUS even when there are less physical CPUs available. Drop the arbitrary '710' value and return num_online_cpus() on x86 as well. The recommendation will match other architectures and will mean 'no CPU overcommit'. For reference, QEMU only queries KVM_CAP_NR_VCPUS to print a warning when the requested vCPU number exceeds it. The static limit of '710' is quite weird as smaller systems with just a few physical CPUs should certainly "recommend" less. Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211111134733.86601-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: Move INVPCID type check from vmx and svm to the common kvm_handle_invpcid()Vipin Sharma2021-11-113-11/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Handle #GP on INVPCID due to an invalid type in the common switch statement instead of relying on the callers (VMX and SVM) to manually validate the type. Unlike INVVPID and INVEPT, INVPCID is not explicitly documented to check the type before reading the operand from memory, so deferring the type validity check until after that point is architecturally allowed. Signed-off-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109174426.2350547-3-vipinsh@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: VMX: Add a helper function to retrieve the GPR index for INVPCID, ↵Vipin Sharma2021-11-113-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | INVVPID, and INVEPT handle_invept(), handle_invvpid(), handle_invpcid() read the same reg2 field in vmcs.VMX_INSTRUCTION_INFO to get the index of the GPR that holds the invalidation type. Add a helper to retrieve reg2 from VMX instruction info to consolidate and document the shift+mask magic. Signed-off-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109174426.2350547-2-vipinsh@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: nVMX: Clean up x2APIC MSR handling for L2Sean Christopherson2021-11-111-39/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clean up the x2APIC MSR bitmap intereption code for L2, which is the last holdout of open coded bitmap manipulations. Freshen up the SDM/PRM comment, rename the function to make it abundantly clear the funky behavior is x2APIC specific, and explain _why_ vmcs01's bitmap is ignored (the previous comment was flat out wrong for x2APIC behavior). No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109013047.2041518-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: VMX: Macrofy the MSR bitmap getters and settersSean Christopherson2021-11-111-60/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add builder macros to generate the MSR bitmap helpers to reduce the amount of copy-paste code, especially with respect to all the magic numbers needed to calc the correct bit location. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109013047.2041518-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: nVMX: Handle dynamic MSR intercept togglingSean Christopherson2021-11-113-110/+111
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Always check vmcs01's MSR bitmap when merging L0 and L1 bitmaps for L2, and always update the relevant bits in vmcs02. This fixes two distinct, but intertwined bugs related to dynamic MSR bitmap modifications. The first issue is that KVM fails to enable MSR interception in vmcs02 for the FS/GS base MSRs if L1 first runs L2 with interception disabled, and later enables interception. The second issue is that KVM fails to honor userspace MSR filtering when preparing vmcs02. Fix both issues simultaneous as fixing only one of the issues (doesn't matter which) would create a mess that no one should have to bisect. Fixing only the first bug would exacerbate the MSR filtering issue as userspace would see inconsistent behavior depending on the whims of L1. Fixing only the second bug (MSR filtering) effectively requires fixing the first, as the nVMX code only knows how to transition vmcs02's bitmap from 1->0. Move the various accessor/mutators that are currently buried in vmx.c into vmx.h so that they can be shared by the nested code. Fixes: 1a155254ff93 ("KVM: x86: Introduce MSR filtering") Fixes: d69129b4e46a ("KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible") Cc: stable@vger.kernel.org Cc: Alexander Graf <graf@amazon.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109013047.2041518-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: nVMX: Query current VMCS when determining if MSR bitmaps are in useSean Christopherson2021-11-111-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Check the current VMCS controls to determine if an MSR write will be intercepted due to MSR bitmaps being disabled. In the nested VMX case, KVM will disable MSR bitmaps in vmcs02 if they're disabled in vmcs12 or if KVM can't map L1's bitmaps for whatever reason. Note, the bad behavior is relatively benign in the current code base as KVM sets all bits in vmcs02's MSR bitmap by default, clears bits if and only if L0 KVM also disables interception of an MSR, and only uses the buggy helper for MSR_IA32_SPEC_CTRL. Because KVM explicitly tests WRMSR before disabling interception of MSR_IA32_SPEC_CTRL, the flawed check will only result in KVM reading MSR_IA32_SPEC_CTRL from hardware when it isn't strictly necessary. Tag the fix for stable in case a future fix wants to use msr_write_intercepted(), in which case a buggy implementation in older kernels could prove subtly problematic. Fixes: d28b387fb74d ("KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211109013047.2041518-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86: Don't update vcpu->arch.pv_eoi.msr_val when a bogus value was ↵Vitaly Kuznetsov2021-11-111-8/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | written to MSR_KVM_PV_EOI_EN When kvm_gfn_to_hva_cache_init() call from kvm_lapic_set_pv_eoi() fails, MSR write to MSR_KVM_PV_EOI_EN results in #GP so it is reasonable to expect that the value we keep internally in KVM wasn't updated. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211108152819.12485-3-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86: Rename kvm_lapic_enable_pv_eoi()Vitaly Kuznetsov2021-11-114-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kvm_lapic_enable_pv_eoi() is a misnomer as the function is also used to disable PV EOI. Rename it to kvm_lapic_set_pv_eoi(). No functional change intended. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211108152819.12485-2-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86: Make sure KVM_CPUID_FEATURES really are KVM_CPUID_FEATURESPaul Durrant2021-11-115-8/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently when kvm_update_cpuid_runtime() runs, it assumes that the KVM_CPUID_FEATURES leaf is located at 0x40000001. This is not true, however, if Hyper-V support is enabled. In this case the KVM leaves will be offset. This patch introdues as new 'kvm_cpuid_base' field into struct kvm_vcpu_arch to track the location of the KVM leaves and function kvm_update_kvm_cpuid_base() (called from kvm_set_cpuid()) to locate the leaves using the 'KVMKVMKVM\0\0\0' signature (which is now given a definition in kvm_para.h). Adjustment of KVM_CPUID_FEATURES will hence now target the correct leaf. NOTE: A new for_each_possible_hypervisor_cpuid_base() macro is intoduced into processor.h to avoid having duplicate code for the iteration over possible hypervisor base leaves. Signed-off-by: Paul Durrant <pdurrant@amazon.com> Message-Id: <20211105095101.5384-3-pdurrant@amazon.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86: Add helper to consolidate core logic of SET_CPUID{2} flowsSean Christopherson2021-11-111-23/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the core logic of SET_CPUID and SET_CPUID2 to a common helper, the only difference between the two ioctls() is the format of the userspace struct. A future fix will add yet more code to the core logic. No functional change intended. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211105095101.5384-2-pdurrant@amazon.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | kvm: mmu: Use fast PF path for access tracking of huge pages when possibleJunaid Shahid2021-11-111-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The fast page fault path bails out on write faults to huge pages in order to accommodate dirty logging. This change adds a check to do that only when dirty logging is actually enabled, so that access tracking for huge pages can still use the fast path for write faults in the common case. Signed-off-by: Junaid Shahid <junaids@google.com> Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211104003359.2201967-1-junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86/mmu: Properly dereference rcu-protected TDP MMU sptep iteratorSean Christopherson2021-11-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wrap the read of iter->sptep in tdp_mmu_map_handle_target_level() with rcu_dereference(). Shadow pages in the TDP MMU, and thus their SPTEs, are protected by rcu. This fixes a Sparse warning at tdp_mmu.c:900:51: warning: incorrect type in argument 1 (different address spaces) expected unsigned long long [usertype] *sptep got unsigned long long [noderef] [usertype] __rcu *[usertype] sptep Fixes: 7158bee4b475 ("KVM: MMU: pass kvm_mmu_page struct to make_spte") Cc: Ben Gardon <bgardon@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211103161833.3769487-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86: inhibit APICv when KVM_GUESTDBG_BLOCKIRQ activeMaxim Levitsky2021-11-114-2/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM_GUESTDBG_BLOCKIRQ relies on interrupts being injected using standard kvm's inject_pending_event, and not via APICv/AVIC. Since this is a debug feature, just inhibit APICv/AVIC while KVM_GUESTDBG_BLOCKIRQ is in use on at least one vCPU. Fixes: 61e5f69ef0837 ("KVM: x86: implement KVM_GUESTDBG_BLOCKIRQ") Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Tested-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211108090245.166408-1-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | kvm: x86: Convert return type of *is_valid_rdpmc_ecx() to boolJim Mattson2021-11-115-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These function names sound like predicates, and they have siblings, *is_valid_msr(), which _are_ predicates. Moreover, there are comments that essentially warn that these functions behave unexpectedly. Flip the polarity of the return values, so that they become predicates, and convert the boolean result to a success/failure code at the outer call site. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20211105202058.1048757-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | KVM: x86: Fix recording of guest steal time / preempted statusDavid Woodhouse2021-11-112-31/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit b043138246a4 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed") we switched to using a gfn_to_pfn_cache for accessing the guest steal time structure in order to allow for an atomic xchg of the preempted field. This has a couple of problems. Firstly, kvm_map_gfn() doesn't work at all for IOMEM pages when the atomic flag is set, which it is in kvm_steal_time_set_preempted(). So a guest vCPU using an IOMEM page for its steal time would never have its preempted field set. Secondly, the gfn_to_pfn_cache is not invalidated in all cases where it should have been. There are two stages to the GFN->PFN conversion; first the GFN is converted to a userspace HVA, and then that HVA is looked up in the process page tables to find the underlying host PFN. Correct invalidation of the latter would require being hooked up to the MMU notifiers, but that doesn't happen---so it just keeps mapping and unmapping the *wrong* PFN after the userspace page tables change. In the !IOMEM case at least the stale page *is* pinned all the time it's cached, so it won't be freed and reused by anyone else while still receiving the steal time updates. The map/unmap dance only takes care of the KVM administrivia such as marking the page dirty. Until the gfn_to_pfn cache handles the remapping automatically by integrating with the MMU notifiers, we might as well not get a kernel mapping of it, and use the perfectly serviceable userspace HVA that we already have. We just need to implement the atomic xchg on the userspace address with appropriate exception handling, which is fairly trivial. Cc: stable@vger.kernel.org Fixes: b043138246a4 ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <3645b9b889dac6438394194bb5586a46b68d581f.camel@infradead.org> [I didn't entirely agree with David's assessment of the usefulness of the gfn_to_pfn cache, and integrated the outcome of the discussion in the above commit message. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | | Merge branch 'kvm-sev-move-context' into kvm-masterPaolo Bonzini2021-11-115-63/+285
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for AMD SEV and SEV-ES intra-host migration support. Intra host migration provides a low-cost mechanism for userspace VMM upgrades. In the common case for intra host migration, we can rely on the normal ioctls for passing data from one VMM to the next. SEV, SEV-ES, and other confidential compute environments make most of this information opaque, and render KVM ioctls such as "KVM_GET_REGS" irrelevant. As a result, we need the ability to pass this opaque metadata from one VMM to the next. The easiest way to do this is to leave this data in the kernel, and transfer ownership of the metadata from one KVM VM (or vCPU) to the next. In-kernel hand off makes it possible to move any data that would be unsafe/impossible for the kernel to hand directly to userspace, and cannot be reproduced using data that can be handed to userspace. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | | KVM: SEV: Add support for SEV-ES intra host migrationPeter Gonda2021-11-111-1/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For SEV-ES to work with intra host migration the VMSAs, GHCB metadata, and other SEV-ES info needs to be preserved along with the guest's memory. Signed-off-by: Peter Gonda <pgonda@google.com> Reviewed-by: Marc Orr <marcorr@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Jim Mattson <jmattson@google.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <20211021174303.385706-4-pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | | KVM: SEV: Add support for SEV intra host migrationPeter Gonda2021-11-115-0/+162
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For SEV to work with intra host migration, contents of the SEV info struct such as the ASID (used to index the encryption key in the AMD SP) and the list of memory regions need to be transferred to the target VM. This change adds a commands for a target VMM to get a source SEV VM's sev info. Signed-off-by: Peter Gonda <pgonda@google.com> Suggested-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Marc Orr <marcorr@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Jim Mattson <jmattson@google.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <20211021174303.385706-3-pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | | KVM: SEV: provide helpers to charge/uncharge misc_cgPaolo Bonzini2021-11-111-7/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid code duplication across all callers of misc_cg_try_charge and misc_cg_uncharge. The resource type for KVM is always derived from sev->es_active, and the quantity is always 1. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | | KVM: generalize "bugged" VM to "dead" VMPaolo Bonzini2021-11-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generalize KVM_REQ_VM_BUGGED so that it can be called even in cases where it is by design that the VM cannot be operated upon. In this case any KVM_BUG_ON should still warn, so introduce a new flag kvm->vm_dead that is separate from kvm->vm_bugged. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | | KVM: SEV: Refactor out sev_es_state structPeter Gonda2021-11-113-56/+61
| | |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move SEV-ES vCPU metadata into new sev_es_state struct from vcpu_svm. Signed-off-by: Peter Gonda <pgonda@google.com> Suggested-by: Tom Lendacky <thomas.lendacky@amd.com> Acked-by: Tom Lendacky <thomas.lendacky@amd.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Cc: Marc Orr <marcorr@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Jim Mattson <jmattson@google.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <20211021174303.385706-2-pgonda@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | | Merge branch 'kvm-guest-sev-migration' into kvm-masterPaolo Bonzini2021-11-119-9/+201
| |\ \ \ \ | | |_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add guest api and guest kernel support for SEV live migration. Introduces a new hypercall to notify the host of changes to the page encryption status. If the page is encrypted then it must be migrated through the SEV firmware or a helper VM sharing the key. If page is not encrypted then it can be migrated normally by userspace. This new hypercall is invoked using paravirt_ops. Conflicts: sev_active() replaced by cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT).
| | * | | x86/kvm: Add kexec support for SEV Live Migration.Ashish Kalra2021-11-111-0/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reset the host's shared pages list related to kernel specific page encryption status settings before we load a new kernel by kexec. We cannot reset the complete shared pages list here as we need to retain the UEFI/OVMF firmware specific settings. The host's shared pages list is maintained for the guest to keep track of all unencrypted guest memory regions, therefore we need to explicitly mark all shared pages as encrypted again before rebooting into the new guest kernel. Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Reviewed-by: Steve Rutherford <srutherford@google.com> Message-Id: <3e051424ab839ea470f88333273d7a185006754f.1629726117.git.ashish.kalra@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | x86/kvm: Add guest support for detecting and enabling SEV Live Migration ↵Ashish Kalra2021-11-113-0/+91
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | feature. The guest support for detecting and enabling SEV Live migration feature uses the following logic : - kvm_init_plaform() checks if its booted under the EFI - If not EFI, i) if kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL), issue a wrmsrl() to enable the SEV live migration support - If EFI, i) If kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL), read the UEFI variable which indicates OVMF support for live migration ii) the variable indicates live migration is supported, issue a wrmsrl() to enable the SEV live migration support The EFI live migration check is done using a late_initcall() callback. Also, ensure that _bss_decrypted section is marked as decrypted in the hypervisor's guest page encryption status tracking. Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Reviewed-by: Steve Rutherford <srutherford@google.com> Message-Id: <b4453e4c87103ebef12217d2505ea99a1c3e0f0f.1629726117.git.ashish.kalra@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | mm: x86: Invoke hypercall when page encryption status is changedBrijesh Singh2021-11-116-9/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Invoke a hypercall when a memory region is changed from encrypted -> decrypted and vice versa. Hypervisor needs to know the page encryption status during the guest migration. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Borislav Petkov <bp@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Steve Rutherford <srutherford@google.com> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Reviewed-by: Borislav Petkov <bp@suse.de> Message-Id: <0a237d5bb08793916c7790a3e653a2cbe7485761.1629726117.git.ashish.kalra@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | * | | x86/kvm: Add AMD SEV specific Hypercall3Brijesh Singh2021-11-111-0/+12
| | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM hypercall framework relies on alternative framework to patch the VMCALL -> VMMCALL on AMD platform. If a hypercall is made before apply_alternative() is called then it defaults to VMCALL. The approach works fine on non SEV guest. A VMCALL would causes #UD, and hypervisor will be able to decode the instruction and do the right things. But when SEV is active, guest memory is encrypted with guest key and hypervisor will not be able to decode the instruction bytes. To highlight the need to provide this interface, capturing the flow of apply_alternatives() : setup_arch() call init_hypervisor_platform() which detects the hypervisor platform the kernel is running under and then the hypervisor specific initialization code can make early hypercalls. For example, KVM specific initialization in case of SEV will try to mark the "__bss_decrypted" section's encryption state via early page encryption status hypercalls. Now, apply_alternatives() is called much later when setup_arch() calls check_bugs(), so we do need some kind of an early, pre-alternatives hypercall interface. Other cases of pre-alternatives hypercalls include marking per-cpu GHCB pages as decrypted on SEV-ES and per-cpu apf_reason, steal_time and kvm_apic_eoi as decrypted for SEV generally. Add SEV specific hypercall3, it unconditionally uses VMMCALL. The hypercall will be used by the SEV guest to notify encrypted pages to the hypervisor. This kvm_sev_hypercall3() function is abstracted and used as follows : All these early hypercalls are made through early_set_memory_XX() interfaces, which in turn invoke pv_ops (paravirt_ops). This early_set_memory_XX() -> pv_ops.mmu.notify_page_enc_status_changed() is a generic interface and can easily have SEV, TDX and any other future platform specific abstractions added to it. Currently, pv_ops.mmu.notify_page_enc_status_changed() callback is setup to invoke kvm_sev_hypercall3() in case of SEV. Similarly, in case of TDX, pv_ops.mmu.notify_page_enc_status_changed() can be setup to a TDX specific callback. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Borislav Petkov <bp@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Steve Rutherford <srutherford@google.com> Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Message-Id: <6fd25c749205dd0b1eb492c60d41b124760cc6ae.1629726117.git.ashish.kalra@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | | Merge branch 'exit-cleanups-for-v5.16' of ↵Linus Torvalds2021-11-131-1/+1
|\ \ \ \ | |/ / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull vm86 fix from Eric Biederman: "Just the removal of an unnecessary (and incorrect) test from a BUG_ON" * 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: signal/vm86_32: Remove pointless test in BUG_ON
| * | | signal/vm86_32: Remove pointless test in BUG_ONEric W. Biederman2021-11-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel test robot <oliver.sang@intel.com> writes[1]: > > Greeting, > > FYI, we noticed the following commit (built with gcc-9): > > commit: 1a4d21a23c4ca7467726be7db9ae8077a62b2c62 ("signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON") > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > in testcase: trinity > version: trinity-static-i386-x86_64-1c734c75-1_2020-01-06 > with following parameters: > > > [ 70.645554][ T3747] kernel BUG at arch/x86/kernel/vm86_32.c:109! > [ 70.646185][ T3747] invalid opcode: 0000 [#1] SMP > [ 70.646682][ T3747] CPU: 0 PID: 3747 Comm: trinity-c6 Not tainted 5.15.0-rc1-00009-g1a4d21a23c4c #1 > [ 70.647598][ T3747] EIP: save_v86_state (arch/x86/kernel/vm86_32.c:109 (discriminator 3)) > [ 70.648113][ T3747] Code: 89 c3 64 8b 35 60 b8 25 c2 83 ec 08 89 55 f0 8b 96 10 19 00 00 89 55 ec e8 c6 2d 0c 00 fb 8b 55 ec 85 d2 74 05 83 3a 00 75 02 <0f> 0b 8b 86 10 19 00 00 8b 4b 38 8b 78 48 31 cf 89 f8 8b 7a 4c 81 > [ 70.650136][ T3747] EAX: 00000001 EBX: f5f49fac ECX: 0000000b EDX: f610b600 > [ 70.650852][ T3747] ESI: f5f79cc0 EDI: f5f79cc0 EBP: f5f49f04 ESP: f5f49ef0 > [ 70.651593][ T3747] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010246 > [ 70.652413][ T3747] CR0: 80050033 CR2: 00004000 CR3: 35fc7000 CR4: 000406d0 > [ 70.653169][ T3747] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 70.653897][ T3747] DR6: fffe0ff0 DR7: 00000400 > [ 70.654382][ T3747] Call Trace: > [ 70.654719][ T3747] arch_do_signal_or_restart (arch/x86/kernel/signal.c:792 arch/x86/kernel/signal.c:867) > [ 70.655288][ T3747] exit_to_user_mode_prepare (kernel/entry/common.c:174 kernel/entry/common.c:209) > [ 70.655854][ T3747] irqentry_exit_to_user_mode (kernel/entry/common.c:126 kernel/entry/common.c:317) > [ 70.656450][ T3747] irqentry_exit (kernel/entry/common.c:406) > [ 70.656897][ T3747] exc_page_fault (arch/x86/mm/fault.c:1535) > [ 70.657369][ T3747] ? sysvec_kvm_asyncpf_interrupt (arch/x86/mm/fault.c:1488) > [ 70.657989][ T3747] handle_exception (arch/x86/entry/entry_32.S:1085) vm86_32.c:109 is: "BUG_ON(!vm86 || !vm86->user_vm86)" When trying to understand the failure Brian Gerst pointed out[2] that the code does not need protection against vm86->user_vm86 being NULL. The copy_from_user code will already handles that case if the address is going to fault. Looking futher I realized that if we care about not allowing struct vm86plus_struct at address 0 it should be do_sys_vm86 (the system call) that does the filtering. Not way down deep when the emulation has completed in save_v86_state. So let's just remove the silly case of attempting to filter a userspace address with a BUG_ON. Existing userspace can't break and it won't make the kernel any more attackable as the userspace access helpers will handle it, if it isn't a good userspace pointer. I have run the reproducer the fuzzer gave me before I made this change and it reproduced, and after I made this change and I have not seen the reported failure. So it does looks like this fixes the reported issue. [1] https://lkml.kernel.org/r/20211112074030.GB19820@xsang-OptiPlex-9020 [2] https://lkml.kernel.org/r/CAMzpN2jkK5sAv-Kg_kVnCEyVySiqeTdUORcC=AdG1gV6r8nUew@mail.gmail.com Suggested-by: Brian Gerst <brgerst@gmail.com> Reported-by: kernel test robot <oliver.sang@intel.com> Tested-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | | | Merge branch 'exit-cleanups-for-v5.16' of ↵Linus Torvalds2021-11-113-9/+7
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull exit cleanups from Eric Biederman: "While looking at some issues related to the exit path in the kernel I found several instances where the code is not using the existing abstractions properly. This set of changes introduces force_fatal_sig a way of sending a signal and not allowing it to be caught, and corrects the misuse of the existing abstractions that I found. A lot of the misuse of the existing abstractions are silly things such as doing something after calling a no return function, rolling BUG by hand, doing more work than necessary to terminate a kernel thread, or calling do_exit(SIGKILL) instead of calling force_sig(SIGKILL). In the review a deficiency in force_fatal_sig and force_sig_seccomp where ptrace or sigaction could prevent the delivery of the signal was found. I have added a change that adds SA_IMMUTABLE to change that makes it impossible to interrupt the delivery of those signals, and allows backporting to fix force_sig_seccomp And Arnd found an issue where a function passed to kthread_run had the wrong prototype, and after my cleanup was failing to build." * 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits) soc: ti: fix wkup_m3_rproc_boot_thread return type signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) exit/r8188eu: Replace the macro thread_exit with a simple return 0 exit/rtl8712: Replace the macro thread_exit with a simple return 0 exit/rtl8723bs: Replace the macro thread_exit with a simple return 0 signal/x86: In emulate_vsyscall force a signal instead of calling do_exit signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails exit/syscall_user_dispatch: Send ordinary signals on failure signal: Implement force_fatal_sig exit/kthread: Have kernel threads return instead of calling do_exit signal/s390: Use force_sigsegv in default_trap_handler signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved. signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON signal/sparc: In setup_tsb_params convert open coded BUG into BUG signal/powerpc: On swapcontext failure force SIGSEGV signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL) signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT signal/sparc32: Remove unreachable do_exit in do_sparc_fault ...
| * | | signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV)Eric W. Biederman2021-10-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that force_fatal_sig exists it is unnecessary and a bit confusing to use force_sigsegv in cases where the simpler force_fatal_sig is wanted. So change every instance we can to make the code clearer. Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Link: https://lkml.kernel.org/r/877de7jrev.fsf@disp2133 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | | signal/x86: In emulate_vsyscall force a signal instead of calling do_exitEric W. Biederman2021-10-291-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Directly calling do_exit with a signal number has the problem that all of the side effects of the signal don't happen, such as killing all of the threads of a process instead of just the calling thread. So replace do_exit(SIGSYS) with force_fatal_sig(SIGSYS) which causes the signal handling to take it's normal path and work as expected. Cc: Andy Lutomirski <luto@kernel.org> Link: https://lkml.kernel.org/r/20211020174406.17889-17-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | | signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.Eric W. Biederman2021-10-251-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update save_v86_state to always complete all of it's work except possibly some of the copies to userspace even if save_v86_state takes a fault. This ensures that the kernel is always in a sane state, even if userspace has done something silly. When save_v86_state takes a fault update it to force userspace to take a SIGSEGV and terminate the userspace application. As Andy pointed out in review of the first version of this change there are races between sigaction and the application terinating. Now that the code has been modified to always perform all save_v86_state's work (except possibly copying to userspace) those races do not matter from a kernel perspective. Forcing the userspace application to terminate (by resetting it's handler to SIGDFL) is there to keep everything as close to the current behavior as possible while removing the unique (and difficult to maintain) use of do_exit. If this new SIGSEGV happens during handle_signal the next time around the exit_to_user_mode_loop, SIGSEGV will be delivered to userspace. All of the callers of handle_vm86_trap and handle_vm86_fault run the exit_to_user_mode_loop before they return to userspace any signal sent to the current task during their execution will be delivered to the current task before that tasks exits to usermode. Cc: Andy Lutomirski <luto@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: x86@kernel.org Cc: H Peter Anvin <hpa@zytor.com> v1: https://lkml.kernel.org/r/20211020174406.17889-10-ebiederm@xmission.com Link: https://lkml.kernel.org/r/877de1xcr6.fsf_-_@disp2133 Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | | signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ONEric W. Biederman2021-10-251-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function save_v86_state is only called when userspace was operating in vm86 mode before entering the kernel. Not having vm86 state in the task_struct should never happen. So transform the hand rolled BUG_ON into an actual BUG_ON to make it clear what is happening. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: x86@kernel.org Cc: H Peter Anvin <hpa@zytor.com> Link: https://lkml.kernel.org/r/20211020174406.17889-9-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | | exit/doublefault: Remove apparently bogus comment about rewind_stack_do_exitEric W. Biederman2021-10-201-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I do not see panic calling rewind_stack_do_exit anywhere, nor can I find anywhere in the history where doublefault_shim has called rewind_stack_do_exit. So I don't think this comment was ever actually correct. Cc: Andy Lutomirski <luto@kernel.org> Fixes: 7d8d8cfdee9a ("x86/doublefault/32: Rewrite the x86_32 #DF handler and unify with 64-bit") Link: https://lkml.kernel.org/r/20211020174406.17889-1-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>