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Diffstat (limited to 'arch/x86/kvm/vmx.c')
-rw-r--r--arch/x86/kvm/vmx.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 023afa0c8887..c829d89e2e63 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -50,6 +50,7 @@
#include <asm/apic.h>
#include <asm/irq_remapping.h>
#include <asm/mmu_context.h>
+#include <asm/nospec-branch.h>
#include "trace.h"
#include "pmu.h"
@@ -899,8 +900,16 @@ static inline short vmcs_field_to_offset(unsigned long field)
{
BUILD_BUG_ON(ARRAY_SIZE(vmcs_field_to_offset_table) > SHRT_MAX);
- if (field >= ARRAY_SIZE(vmcs_field_to_offset_table) ||
- vmcs_field_to_offset_table[field] == 0)
+ if (field >= ARRAY_SIZE(vmcs_field_to_offset_table))
+ return -ENOENT;
+
+ /*
+ * FIXME: Mitigation for CVE-2017-5753. To be replaced with a
+ * generic mechanism.
+ */
+ asm("lfence");
+
+ if (vmcs_field_to_offset_table[field] == 0)
return -ENOENT;
return vmcs_field_to_offset_table[field];
@@ -1887,7 +1896,7 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
{
u32 eb;
- eb = (1u << PF_VECTOR) | (1u << MC_VECTOR) |
+ eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
(1u << DB_VECTOR) | (1u << AC_VECTOR);
if ((vcpu->guest_debug &
(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)) ==
@@ -1905,8 +1914,6 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
*/
if (is_guest_mode(vcpu))
eb |= get_vmcs12(vcpu)->exception_bitmap;
- else
- eb |= 1u << UD_VECTOR;
vmcs_write32(EXCEPTION_BITMAP, eb);
}
@@ -5917,7 +5924,6 @@ static int handle_exception(struct kvm_vcpu *vcpu)
return 1; /* already handled by vmx_vcpu_run() */
if (is_invalid_opcode(intr_info)) {
- WARN_ON_ONCE(is_guest_mode(vcpu));
er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD);
if (er == EMULATE_USER_EXIT)
return 0;
@@ -9415,6 +9421,7 @@ 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"
@@ -9431,12 +9438,23 @@ 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"
@@ -9473,6 +9491,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
#endif
);
+ /* Eliminate branch target predictions from guest mode */
+ vmexit_fill_RSB();
+
/* MSR_IA32_DEBUGCTLMSR is zeroed on vmexit. Restore it if needed */
if (debugctlmsr)
update_debugctlmsr(debugctlmsr);