From 38244295d9e7663919d606cb9a005f7dee3b7799 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Wed, 3 Jan 2018 14:31:38 -0800 Subject: 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 Signed-off-by: Jim Mattson Reviewed-by: Eric Northup Reviewed-by: Benjamin Serebrin Reviewed-by: Andrew Honig [Paolo: Add AMD bits, Signed-off-by: Tom Lendacky ] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'arch/x86/kvm/svm.c') 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 @@ -4964,6 +4964,25 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) "mov %%r13, %c[r13](%[svm]) \n\t" "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 : -- cgit v1.2.3