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* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234Thomas Gleixner2019-06-191-12/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Enrico Weigelt <info@metux.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: arm/arm64: Context-switch ptrauth registersMark Rutland2019-04-241-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When pointer authentication is supported, a guest may wish to use it. This patch adds the necessary KVM infrastructure for this to work, with a semi-lazy context switch of the pointer auth state. Pointer authentication feature is only enabled when VHE is built in the kernel and present in the CPU implementation so only VHE code paths are modified. When we schedule a vcpu, we disable guest usage of pointer authentication instructions and accesses to the keys. While these are disabled, we avoid context-switching the keys. When we trap the guest trying to use pointer authentication functionality, we change to eagerly context-switching the keys, and enable the feature. The next time the vcpu is scheduled out/in, we start again. However the host key save is optimized and implemented inside ptrauth instruction/register access trap. Pointer authentication consists of address authentication and generic authentication, and CPUs in a system might have varied support for either. Where support for either feature is not uniform, it is hidden from guests via ID register emulation, as a result of the cpufeature framework in the host. Unfortunately, address authentication and generic authentication cannot be trapped separately, as the architecture provides a single EL2 trap covering both. If we wish to expose one without the other, we cannot prevent a (badly-written) guest from intermittently using a feature which is not uniformly supported (when scheduled on a physical CPU which supports the relevant feature). Hence, this patch expects both type of authentication to be present in a cpu. This switch of key is done from guest enter/exit assembly as preparation for the upcoming in-kernel pointer authentication support. Hence, these key switching routines are not implemented in C code as they may cause pointer authentication key signing error in some situations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> [Only VHE, key switch in full assembly, vcpu_has_ptrauth checks , save host key in ptrauth exception trap] Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: kvmarm@lists.cs.columbia.edu [maz: various fixups] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* arm64: entry: Place an SB sequence following an ERET instructionWill Deacon2018-12-061-0/+1
| | | | | | | | | | | | | Some CPUs can speculate past an ERET instruction and potentially perform speculative accesses to memory before processing the exception return. Since the register state is often controlled by a lower privilege level at the point of an ERET, this could potentially be used as part of a side-channel attack. This patch emits an SB sequence after each ERET so that speculation is held up on exception return. Signed-off-by: Will Deacon <will.deacon@arm.com>
* KVM: arm64: Invoke FPSIMD context switch trap from CDave Martin2018-05-251-30/+0
| | | | | | | | | | | | | | | | | | | | | | | | The conversion of the FPSIMD context switch trap code to C has added some overhead to calling it, due to the need to save registers that the procedure call standard defines as caller-saved. So, perhaps it is no longer worth invoking this trap handler quite so early. Instead, we can invoke it from fixup_guest_exit(), with little likelihood of increasing the overhead much further. As a convenience, this patch gives __hyp_switch_fpsimd() the same return semantics fixup_guest_exit(). For now there is no possibility of a spurious FPSIMD trap, so the function always returns true, but this allows it to be tail-called with a single return statement. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* KVM: arm64: Convert lazy FPSIMD context switch trap to CDave Martin2018-05-251-35/+22
| | | | | | | | | | | | | To make the lazy FPSIMD context switch trap code easier to hack on, this patch converts it to C. This is not amazingly efficient, but the trap should typically only be taken once per host context switch. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* arm64: KVM: Use SMCCC_ARCH_WORKAROUND_1 for Falkor BP hardeningShanker Donthineni2018-04-111-12/+0
| | | | | | | | | | | | | The function SMCCC_ARCH_WORKAROUND_1 was introduced as part of SMC V1.1 Calling Convention to mitigate CVE-2017-5715. This patch uses the standard call SMCCC_ARCH_WORKAROUND_1 for Falkor chips instead of Silicon provider service ID 0xC2001700. Cc: <stable@vger.kernel.org> # 4.14+ Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> [maz: reworked errata framework integration] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* Revert "arm64: KVM: Use SMCCC_ARCH_WORKAROUND_1 for Falkor BP hardening"Marc Zyngier2018-03-281-0/+12
| | | | | | | | | Creates far too many conflicts with arm64/for-next/core, to be resent post -rc1. This reverts commit f9f5dc19509bbef6f5e675346f1a7d7b846bdb12. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* arm64: KVM: Use SMCCC_ARCH_WORKAROUND_1 for Falkor BP hardeningShanker Donthineni2018-03-191-12/+0
| | | | | | | | | | | The function SMCCC_ARCH_WORKAROUND_1 was introduced as part of SMC V1.1 Calling Convention to mitigate CVE-2017-5715. This patch uses the standard call SMCCC_ARCH_WORKAROUND_1 for Falkor chips instead of Silicon provider service ID 0xC2001700. Cc: <stable@vger.kernel.org> # 4.14+ Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* KVM: arm64: Avoid storing the vcpu pointer on the stackChristoffer Dall2018-03-191-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We already have the percpu area for the host cpu state, which points to the VCPU, so there's no need to store the VCPU pointer on the stack on every context switch. We can be a little more clever and just use tpidr_el2 for the percpu offset and load the VCPU pointer from the host context. This has the benefit of being able to retrieve the host context even when our stack is corrupted, and it has a potential performance benefit because we trade a store plus a load for an mrs and a load on a round trip to the guest. This does require us to calculate the percpu offset without including the offset from the kernel mapping of the percpu array to the linear mapping of the array (which is what we store in tpidr_el1), because a PC-relative generated address in EL2 is already giving us the hyp alias of the linear mapping of a kernel address. We do this in __cpu_init_hyp_mode() by using kvm_ksym_ref(). The code that accesses ESR_EL2 was previously using an alternative to use the _EL1 accessor on VHE systems, but this was actually unnecessary as the _EL1 accessor aliases the ESR_EL2 register on VHE, and the _EL2 accessor does the same thing on both systems. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* KVM: arm64: Handle RAS SErrors from EL2 on guest exitJames Morse2018-01-161-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We expect to have firmware-first handling of RAS SErrors, with errors notified via an APEI method. For systems without firmware-first, add some minimal handling to KVM. There are two ways KVM can take an SError due to a guest, either may be a RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO, or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit. The current SError from EL2 code unmasks SError and tries to fence any pending SError into a single instruction window. It then leaves SError unmasked. With the v8.2 RAS Extensions we may take an SError for a 'corrected' error, but KVM is only able to handle SError from EL2 if they occur during this single instruction window... The RAS Extensions give us a new instruction to synchronise and consume SErrors. The RAS Extensions document (ARM DDI0587), '2.4.1 ESB and Unrecoverable errors' describes ESB as synchronising SError interrupts generated by 'instructions, translation table walks, hardware updates to the translation tables, and instruction fetches on the same PE'. This makes ESB equivalent to KVMs existing 'dsb, mrs-daifclr, isb' sequence. Use the alternatives to synchronise and consume any SError using ESB instead of unmasking and taking the SError. Set ARM_EXIT_WITH_SERROR_BIT in the exit_code so that we can restart the vcpu if it turns out this SError has no impact on the vcpu. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* KVM: arm64: Store vcpu on the stack during __guest_enter()James Morse2018-01-131-3/+7
| | | | | | | | | | | | | | | | | | KVM uses tpidr_el2 as its private vcpu register, which makes sense for non-vhe world switch as only KVM can access this register. This means vhe Linux has to use tpidr_el1, which KVM has to save/restore as part of the host context. If the SDEI handler code runs behind KVMs back, it mustn't access any per-cpu variables. To allow this on systems with vhe we need to make the host use tpidr_el2, saving KVM from save/restoring it. __guest_enter() stores the host_ctxt on the stack, do the same with the vcpu. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Christoffer Dall <cdall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: Implement branch predictor hardening for FalkorShanker Donthineni2018-01-081-0/+12
| | | | | | | | | | | | | Falkor is susceptible to branch predictor aliasing and can theoretically be attacked by malicious code. This patch implements a mitigation for these attacks, preventing any malicious entries from affecting other victim contexts. Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> [will: fix label name when !CONFIG_KVM and remove references to MIDR_FALKOR] Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* arm64: KVM: Handle async aborts delivered while at EL2Marc Zyngier2016-09-081-1/+32
| | | | | | | | | | | | | | | If EL1 generates an asynchronous abort and then traps into EL2 before the abort has been delivered, we may end-up with the abort firing at the worse possible place: on the host. In order to avoid this, it is necessary to take the abort at EL2, by clearing the PSTATE.A bit. In order to survive this abort, we do it at a point where we're in a known state with respect to the world switch, and handle the resulting exception, overloading the exit code in the process. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: KVM: VHE: reset PSTATE.PAN on entry to EL2Vladimir Murzin2016-09-081-0/+2
| | | | | | | | | | | | | | | | | | SCTLR_EL2.SPAN bit controls what happens with the PSTATE.PAN bit on an exception. However, this bit has no effect on the PSTATE.PAN when HCR_EL2.E2H or HCR_EL2.TGE is unset. Thus when VHE is used and exception taken from a guest PSTATE.PAN bit left unchanged and we continue with a value guest has set. To address that always reset PSTATE.PAN on entry from EL1. Fixes: 1f364c8c48a0 ("arm64: VHE: Add support for running Linux in EL2 mode") Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Reviewed-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: <stable@vger.kernel.org> # v4.6+ Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: KVM: Optimize __guest_enter/exit() to save a few instructionsShanker Donthineni2016-09-081-51/+50
| | | | | | | | | | | | | | We are doing an unnecessary stack push/pop operation when restoring the guest registers x0-x18 in __guest_enter(). This patch saves the two instructions by using x18 as a base register. No need to store the vcpu context pointer in stack because it is redundant, the same information is available in tpidr_el2. The function __guest_exit() calling convention is slightly modified, caller only pushes the regs x0-x1 to stack instead of regs x0-x3. Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: KVM: Simplify HYP init/teardownMarc Zyngier2016-07-031-19/+0
| | | | | | | | | Now that we only have the "merged page tables" case to deal with, there is a bunch of things we can simplify in the HYP code (both at init and teardown time). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: kvm: Fix kvm teardown for systems using the extended idmapJames Morse2016-05-031-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If memory is located above 1<<VA_BITS, kvm adds an extra level to its page tables, merging the runtime tables and boot tables that contain the idmap. This lets us avoid the trampoline dance during initialisation. This also means there is no trampoline page mapped, so __cpu_reset_hyp_mode() can't call __kvm_hyp_reset() in this page. The good news is the idmap is still mapped, so we don't need the trampoline page. The bad news is we can't call it directly as the idmap is above HYP_PAGE_OFFSET, so its address is masked by kvm_call_hyp. Add a function __extended_idmap_trampoline which will branch into __kvm_hyp_reset in the idmap, change kvm_hyp_reset_entry() to return this address if __kvm_cpu_uses_extended_idmap(). In this case __kvm_hyp_reset() will still switch to the boot tables (which are the merged tables that were already in use), and branch into the idmap (where it already was). This fixes boot failures on these systems, where we fail to execute the missing trampoline page when tearing down kvm in init_subsystems(): [ 2.508922] kvm [1]: 8-bit VMID [ 2.512057] kvm [1]: Hyp mode initialized successfully [ 2.517242] kvm [1]: interrupt-controller@e1140000 IRQ13 [ 2.522622] kvm [1]: timer IRQ3 [ 2.525783] Kernel panic - not syncing: HYP panic: [ 2.525783] PS:200003c9 PC:0000007ffffff820 ESR:86000005 [ 2.525783] FAR:0000007ffffff820 HPFAR:00000000003ffff0 PAR:0000000000000000 [ 2.525783] VCPU: (null) [ 2.525783] [ 2.547667] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.6.0-rc5+ #1 [ 2.555137] Hardware name: Default string Default string/Default string, BIOS ROD0084E 09/03/2015 [ 2.563994] Call trace: [ 2.566432] [<ffffff80080888d0>] dump_backtrace+0x0/0x240 [ 2.571818] [<ffffff8008088b24>] show_stack+0x14/0x20 [ 2.576858] [<ffffff80083423ac>] dump_stack+0x94/0xb8 [ 2.581899] [<ffffff8008152130>] panic+0x10c/0x250 [ 2.586677] [<ffffff8008152024>] panic+0x0/0x250 [ 2.591281] SMP: stopping secondary CPUs [ 3.649692] SMP: failed to stop secondary CPUs 0-2,4-7 [ 3.654818] Kernel Offset: disabled [ 3.658293] Memory Limit: none [ 3.661337] ---[ end Kernel panic - not syncing: HYP panic: [ 3.661337] PS:200003c9 PC:0000007ffffff820 ESR:86000005 [ 3.661337] FAR:0000007ffffff820 HPFAR:00000000003ffff0 PAR:0000000000000000 [ 3.661337] VCPU: (null) [ 3.661337] Reported-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* arm64: KVM: VHE: Add fpsimd enabling on guest accessMarc Zyngier2016-02-291-0/+6
| | | | | | | | | | Despite the fact that a VHE enabled kernel runs at EL2, it uses CPACR_EL1 to trap FPSIMD access. Add the required alternative code to re-enable guest FPSIMD access when it has trapped to EL2. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* arm64: KVM: Turn system register numbers to an enumMarc Zyngier2015-12-141-2/+1
| | | | | | | | | | | | Having the system register numbers as #defines has been a pain since day one, as the ordering is pretty fragile, and moving things around leads to renumbering and epic conflict resolutions. Now that we're mostly acessing the sysreg file in C, an enum is a much better type to use, and we can clean things up a bit. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: KVM: Implement TLB handlingMarc Zyngier2015-12-141-0/+1
| | | | | | | | Implement the TLB handling as a direct translation of the assembly code version. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: KVM: Implement fpsimd save/restoreMarc Zyngier2015-12-141-1/+31
| | | | | | | | Implement the fpsimd save restore, keeping the lazy part in assembler (as returning to C would be overkill). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
* arm64: KVM: Implement guest entryMarc Zyngier2015-12-141-0/+130
Contrary to the previous patch, the guest entry is fairly different from its assembly counterpart, mostly because it is only concerned with saving/restoring the GP registers, and nothing else. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>