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* KVM: x86/xen: Add support for vCPU runstate informationDavid Woodhouse2021-03-021-0/+286
| | | | | | | | | | | | | | | | | | | | | | | | | | | This is how Xen guests do steal time accounting. The hypervisor records the amount of time spent in each of running/runnable/blocked/offline states. In the Xen accounting, a vCPU is still in state RUNSTATE_running while in Xen for a hypercall or I/O trap, etc. Only if Xen explicitly schedules does the state become RUNSTATE_blocked. In KVM this means that even when the vCPU exits the kvm_run loop, the state remains RUNSTATE_running. The VMM can explicitly set the vCPU to RUNSTATE_blocked by using the KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT attribute, and can also use KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST to retrospectively add a given amount of time to the blocked state and subtract it from the running state. The state_entry_time corresponds to get_kvmclock_ns() at the time the vCPU entered the current state, and the total times of all four states should always add up to state_entry_time. Co-developed-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20210301125309.874953-2-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86/xen: Fix return code when clearing vcpu_info and vcpu_time_infoDavid Woodhouse2021-03-021-0/+4
| | | | | | | | | | | | | When clearing the per-vCPU shared regions, set the return value to zero to indicate success. This was causing spurious errors to be returned to userspace on soft reset. Also add a paranoid BUILD_BUG_ON() for compat structure compatibility. Fixes: 0c165b3c01fe ("KVM: x86/xen: Allow reset of Xen attributes") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20210301125309.874953-1-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86/xen: Allow reset of Xen attributesDavid Woodhouse2021-02-091-10/+28
| | | | | | | | | | In order to support Xen SHUTDOWN_soft_reset (for guest kexec, etc.) the VMM needs to be able to tear everything down and return the Xen features to a clean slate. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20210208232326.1830370-1-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: hyper-v: Make Hyper-V emulation enablement conditionalVitaly Kuznetsov2021-02-091-1/+1
| | | | | | | | | | | | | | | | | | | Hyper-V emulation is enabled in KVM unconditionally. This is bad at least from security standpoint as it is an extra attack surface. Ideally, there should be a per-VM capability explicitly enabled by VMM but currently it is not the case and we can't mandate one without breaking backwards compatibility. We can, however, check guest visible CPUIDs and only enable Hyper-V emulation when "Hv#1" interface was exposed in HYPERV_CPUID_INTERFACE. Note, VMMs are free to act in any sequence they like, e.g. they can try to set MSRs first and CPUIDs later so we still need to allow the host to read/write Hyper-V specific MSRs unconditionally. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20210126134816.1880136-14-vkuznets@redhat.com> [Add selftest vcpu_set_hv_cpuid API to avoid breaking xen_vmcall_test. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86/xen: Use hva_t for holding hypercall page addressSean Christopherson2021-02-091-2/+6
| | | | | | | | | | | | | | | | | | | | Use hva_t, a.k.a. unsigned long, for the local variable that holds the hypercall page address. On 32-bit KVM, gcc complains about using a u64 due to the implicit cast from a 64-bit value to a 32-bit pointer. arch/x86/kvm/xen.c: In function ‘kvm_xen_write_hypercall_page’: arch/x86/kvm/xen.c:300:22: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast] 300 | page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); Cc: Joao Martins <joao.m.martins@oracle.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210208201502.1239867-1-seanjc@google.com> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86/xen: Remove extra unlock in kvm_xen_hvm_set_attr()David Woodhouse2021-02-091-2/+0
| | | | | | | | | | This accidentally ended up locking and then immediately unlocking kvm->lock at the beginning of the function. Fix it. Fixes: a76b9641ad1c ("KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTR") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20210208232326.1830370-2-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86/xen: Add event channel interrupt vector upcallDavid Woodhouse2021-02-041-0/+53
| | | | | | | | | | | | | | | | | | | | | | It turns out that we can't handle event channels *entirely* in userspace by delivering them as ExtINT, because KVM is a bit picky about when it accepts ExtINT interrupts from a legacy PIC. The in-kernel local APIC has to have LVT0 configured in APIC_MODE_EXTINT and unmasked, which isn't necessarily the case for Xen guests especially on secondary CPUs. To cope with this, add kvm_xen_get_interrupt() which checks the evtchn_pending_upcall field in the Xen vcpu_info, and delivers the Xen upcall vector (configured by KVM_XEN_ATTR_TYPE_UPCALL_VECTOR) if it's set regardless of LAPIC LVT0 configuration. This gives us the minimum support we need for completely userspace-based implementation of event channels. This does mean that vcpu_enter_guest() needs to check for the evtchn_pending_upcall flag being set, because it can't rely on someone having set KVM_REQ_EVENT unless we were to add some way for userspace to do so manually. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: register vcpu time info regionJoao Martins2021-02-041-0/+18
| | | | | | | | | Allow the Xen emulated guest the ability to register secondary vcpu time information. On Xen guests this is used in order to be mapped to userspace and hence allow vdso gettimeofday to work. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: setup pvclock updatesJoao Martins2021-02-041-2/+3
| | | | | | | | | | Parameterise kvm_setup_pvclock_page() a little bit so that it can be invoked for different gfn_to_hva_cache structures, and with different offsets. Then we can invoke it for the normal KVM pvclock and also for the Xen one in the vcpu_info. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: register vcpu infoJoao Martins2021-02-041-1/+24
| | | | | | | | | The vcpu info supersedes the per vcpu area of the shared info page and the guest vcpus will use this instead. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: Add KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTRDavid Woodhouse2021-02-041-0/+30
| | | | | | This will be used for per-vCPU setup such as runstate and vcpu_info. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: update wallclock regionJoao Martins2021-02-041-3/+30
| | | | | | | | | | Wallclock on Xen is written in the shared_info page. To that purpose, export kvm_write_wall_clock() and pass on the GPA of its location to populate the shared_info wall clock data. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: register shared_info pageJoao Martins2021-02-041-4/+36
| | | | | | | | Add KVM_XEN_ATTR_TYPE_SHARED_INFO to allow hypervisor to know where the guest's shared info page is. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: latch long_mode when hypercall page is set upDavid Woodhouse2021-02-041-1/+15
| | | | Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTRJoao Martins2021-02-041-0/+30
| | | | | | | This will be used to set up shared info pages etc. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: Add kvm_xen_enabled static keyDavid Woodhouse2021-02-041-0/+17
| | | | | | | | The code paths for Xen support are all fairly lightweight but if we hide them behind this, they're even *more* lightweight for any system which isn't actually hosting Xen guests. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: Move KVM_XEN_HVM_CONFIG handling to xen.cDavid Woodhouse2021-02-041-0/+18
| | | | | | | This is already more complex than the simple memcpy it originally had. Move it to xen.c with the rest of the Xen support. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: Fix coexistence of Xen and Hyper-V hypercallsJoao Martins2021-02-041-0/+6
| | | | | | | | | | | | | | Disambiguate Xen vs. Hyper-V calls by adding 'orl $0x80000000, %eax' at the start of the Hyper-V hypercall page when Xen hypercalls are also enabled. That bit is reserved in the Hyper-V ABI, and those hypercall numbers will never be used by Xen (because it does precisely the same trick). Switch to using kvm_vcpu_write_guest() while we're at it, instead of open-coding it. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
* KVM: x86/xen: intercept xen hypercalls if enabledJoao Martins2021-02-041-0/+142
Add a new exit reason for emulator to handle Xen hypercalls. Since this means KVM owns the ABI, dispense with the facility for the VMM to provide its own copy of the hypercall pages; just fill them in directly using VMCALL/VMMCALL as we do for the Hyper-V hypercall page. This behaviour is enabled by a new INTERCEPT_HCALL flag in the KVM_XEN_HVM_CONFIG ioctl structure, and advertised by the same flag being returned from the KVM_CAP_XEN_HVM check. Rename xen_hvm_config() to kvm_xen_write_hypercall_page() and move it to the nascent xen.c while we're at it, and add a test case. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>