[PATCH 4.14 015/118] kvm: vmx: Scrub hardware GPRs at VM-exit

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

--

From: Jim Mattson 

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 +++
 arch/x86/kvm/vmx.c |   14 +-
 2 files changed, 32 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -4965,6 +4965,25 @@ static void svm_vcpu_run(struct kvm_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),
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9405,6 +9405,7 @@ static void __noclone vmx_vcpu_run(struc
/* 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"
@@ -9421,12 +9422,23 @@ static void __noclone vmx_vcpu_run(struc
"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"

[PATCH 4.14 015/118] kvm: vmx: Scrub hardware GPRs at VM-exit

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

--

From: Jim Mattson 

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 +++
 arch/x86/kvm/vmx.c |   14 +-
 2 files changed, 32 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -4965,6 +4965,25 @@ static void svm_vcpu_run(struct kvm_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),
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9405,6 +9405,7 @@ static void __noclone vmx_vcpu_run(struc
/* 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"
@@ -9421,12 +9422,23 @@ static void __noclone vmx_vcpu_run(struc
"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"