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1 | From c59a61438e9a8f24a50171ac9d3b98e8f3719d07 Mon Sep 17 00:00:00 2001 |
2 | From: Jim Mattson <jmattson@google.com> | |
3 | Date: Wed, 3 Jan 2018 14:31:38 -0800 | |
b378f209 | 4 | Subject: [PATCH 232/233] kvm: vmx: Scrub hardware GPRs at VM-exit |
7c7389df FG |
5 | MIME-Version: 1.0 |
6 | Content-Type: text/plain; charset=UTF-8 | |
7 | Content-Transfer-Encoding: 8bit | |
8 | ||
9 | Guest GPR values are live in the hardware GPRs at VM-exit. Do not | |
10 | leave any guest values in hardware GPRs after the guest GPR values are | |
11 | saved to the vcpu_vmx structure. | |
12 | ||
13 | This is a partial mitigation for CVE 2017-5715 and CVE 2017-5753. | |
14 | Specifically, it defeats the Project Zero PoC for CVE 2017-5715. | |
15 | ||
16 | Suggested-by: Eric Northup <digitaleric@google.com> | |
17 | Signed-off-by: Jim Mattson <jmattson@google.com> | |
18 | Reviewed-by: Eric Northup <digitaleric@google.com> | |
19 | Reviewed-by: Benjamin Serebrin <serebrin@google.com> | |
20 | Reviewed-by: Andrew Honig <ahonig@google.com> | |
21 | Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com> | |
22 | --- | |
23 | arch/x86/kvm/vmx.c | 14 +++++++++++++- | |
24 | 1 file changed, 13 insertions(+), 1 deletion(-) | |
25 | ||
26 | diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c | |
27 | index d61986a36575..9b4256fd589a 100644 | |
28 | --- a/arch/x86/kvm/vmx.c | |
29 | +++ b/arch/x86/kvm/vmx.c | |
30 | @@ -9140,6 +9140,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) | |
31 | /* Save guest registers, load host registers, keep flags */ | |
32 | "mov %0, %c[wordsize](%%" _ASM_SP ") \n\t" | |
33 | "pop %0 \n\t" | |
34 | + "setbe %c[fail](%0)\n\t" | |
35 | "mov %%" _ASM_AX ", %c[rax](%0) \n\t" | |
36 | "mov %%" _ASM_BX ", %c[rbx](%0) \n\t" | |
37 | __ASM_SIZE(pop) " %c[rcx](%0) \n\t" | |
38 | @@ -9156,12 +9157,23 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) | |
39 | "mov %%r13, %c[r13](%0) \n\t" | |
40 | "mov %%r14, %c[r14](%0) \n\t" | |
41 | "mov %%r15, %c[r15](%0) \n\t" | |
42 | + "xor %%r8d, %%r8d \n\t" | |
43 | + "xor %%r9d, %%r9d \n\t" | |
44 | + "xor %%r10d, %%r10d \n\t" | |
45 | + "xor %%r11d, %%r11d \n\t" | |
46 | + "xor %%r12d, %%r12d \n\t" | |
47 | + "xor %%r13d, %%r13d \n\t" | |
48 | + "xor %%r14d, %%r14d \n\t" | |
49 | + "xor %%r15d, %%r15d \n\t" | |
50 | #endif | |
51 | "mov %%cr2, %%" _ASM_AX " \n\t" | |
52 | "mov %%" _ASM_AX ", %c[cr2](%0) \n\t" | |
53 | ||
54 | + "xor %%eax, %%eax \n\t" | |
55 | + "xor %%ebx, %%ebx \n\t" | |
56 | + "xor %%esi, %%esi \n\t" | |
57 | + "xor %%edi, %%edi \n\t" | |
58 | "pop %%" _ASM_BP "; pop %%" _ASM_DX " \n\t" | |
59 | - "setbe %c[fail](%0) \n\t" | |
60 | ".pushsection .rodata \n\t" | |
61 | ".global vmx_return \n\t" | |
62 | "vmx_return: " _ASM_PTR " 2b \n\t" | |
63 | -- | |
64 | 2.14.2 | |
65 |