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- From c59a61438e9a8f24a50171ac9d3b98e8f3719d07 Mon Sep 17 00:00:00 2001
- From: Jim Mattson <[email protected]>
- Date: Wed, 3 Jan 2018 14:31:38 -0800
- Subject: [PATCH 232/232] kvm: vmx: Scrub hardware GPRs at VM-exit
- MIME-Version: 1.0
- Content-Type: text/plain; charset=UTF-8
- Content-Transfer-Encoding: 8bit
- 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 <[email protected]>
- Signed-off-by: Jim Mattson <[email protected]>
- Reviewed-by: Eric Northup <[email protected]>
- Reviewed-by: Benjamin Serebrin <[email protected]>
- Reviewed-by: Andrew Honig <[email protected]>
- Signed-off-by: Fabian Grünbichler <[email protected]>
- ---
- arch/x86/kvm/vmx.c | 14 +++++++++++++-
- 1 file changed, 13 insertions(+), 1 deletion(-)
- diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
- index d61986a36575..9b4256fd589a 100644
- --- a/arch/x86/kvm/vmx.c
- +++ b/arch/x86/kvm/vmx.c
- @@ -9140,6 +9140,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
- /* Save guest registers, load host registers, keep flags */
- "mov %0, %c[wordsize](%%" _ASM_SP ") \n\t"
- "pop %0 \n\t"
- + "setbe %c[fail](%0)\n\t"
- "mov %%" _ASM_AX ", %c[rax](%0) \n\t"
- "mov %%" _ASM_BX ", %c[rbx](%0) \n\t"
- __ASM_SIZE(pop) " %c[rcx](%0) \n\t"
- @@ -9156,12 +9157,23 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
- "mov %%r13, %c[r13](%0) \n\t"
- "mov %%r14, %c[r14](%0) \n\t"
- "mov %%r15, %c[r15](%0) \n\t"
- + "xor %%r8d, %%r8d \n\t"
- + "xor %%r9d, %%r9d \n\t"
- + "xor %%r10d, %%r10d \n\t"
- + "xor %%r11d, %%r11d \n\t"
- + "xor %%r12d, %%r12d \n\t"
- + "xor %%r13d, %%r13d \n\t"
- + "xor %%r14d, %%r14d \n\t"
- + "xor %%r15d, %%r15d \n\t"
- #endif
- "mov %%cr2, %%" _ASM_AX " \n\t"
- "mov %%" _ASM_AX ", %c[cr2](%0) \n\t"
-
- + "xor %%eax, %%eax \n\t"
- + "xor %%ebx, %%ebx \n\t"
- + "xor %%esi, %%esi \n\t"
- + "xor %%edi, %%edi \n\t"
- "pop %%" _ASM_BP "; pop %%" _ASM_DX " \n\t"
- - "setbe %c[fail](%0) \n\t"
- ".pushsection .rodata \n\t"
- ".global vmx_return \n\t"
- "vmx_return: " _ASM_PTR " 2b \n\t"
- --
- 2.14.2
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