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| author | Jim Mattson <jmattson@google.com> | 2018-01-03 14:31:38 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-17 09:45:18 +0100 |
| commit | 38244295d9e7663919d606cb9a005f7dee3b7799 (patch) | |
| tree | 03085bc1356a52be72af32d60142aa59a27f5765 /arch/x86/kvm/svm.c | |
| parent | 0196bdf590e3b0530a538c162a3d8fe46a363b5b (diff) | |
| download | linux-stable-38244295d9e7663919d606cb9a005f7dee3b7799.tar.gz linux-stable-38244295d9e7663919d606cb9a005f7dee3b7799.tar.bz2 linux-stable-38244295d9e7663919d606cb9a005f7dee3b7799.zip | |
kvm: vmx: Scrub hardware GPRs at VM-exit
commit 0cb5b30698fdc8f6b4646012e3acb4ddce430788 upstream.
Guest GPR values are live in the hardware GPRs at VM-exit. Do not
leave any guest values in hardware GPRs after the guest GPR values are
saved to the vcpu_vmx structure.
This is a partial mitigation for CVE 2017-5715 and CVE 2017-5753.
Specifically, it defeats the Project Zero PoC for CVE 2017-5715.
Suggested-by: Eric Northup <digitaleric@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Eric Northup <digitaleric@google.com>
Reviewed-by: Benjamin Serebrin <serebrin@google.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
[Paolo: Add AMD bits, Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 17fb6c6d939a..714e4804cbe2 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -4965,6 +4965,25 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) "mov %%r14, %c[r14](%[svm]) \n\t" "mov %%r15, %c[r15](%[svm]) \n\t" #endif + /* + * Clear host registers marked as clobbered to prevent + * speculative use. + */ + "xor %%" _ASM_BX ", %%" _ASM_BX " \n\t" + "xor %%" _ASM_CX ", %%" _ASM_CX " \n\t" + "xor %%" _ASM_DX ", %%" _ASM_DX " \n\t" + "xor %%" _ASM_SI ", %%" _ASM_SI " \n\t" + "xor %%" _ASM_DI ", %%" _ASM_DI " \n\t" +#ifdef CONFIG_X86_64 + "xor %%r8, %%r8 \n\t" + "xor %%r9, %%r9 \n\t" + "xor %%r10, %%r10 \n\t" + "xor %%r11, %%r11 \n\t" + "xor %%r12, %%r12 \n\t" + "xor %%r13, %%r13 \n\t" + "xor %%r14, %%r14 \n\t" + "xor %%r15, %%r15 \n\t" +#endif "pop %%" _ASM_BP : : [svm]"a"(svm), |