diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2020-04-13 03:17:58 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-04-14 04:21:21 -0400 |
| commit | f14eec0a32038f2d6c05b8ea91c7701f65ce7418 (patch) | |
| tree | 6bd3c42848e12a26db69f8c145bcdeb402fad7cb /arch/x86/kvm | |
| parent | 9ef1530c0c1bb182d7f60165946bd027ff49282e (diff) | |
KVM: SVM: move more vmentry code to assembly
Manipulate IF around vmload/vmsave to remove the confusing usage of
local_irq_enable where interrupts are actually disabled via GIF.
And stuff the RSB immediately without waiting for a RET to avoid
Spectre-v2 attacks.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 7 | ||||
| -rw-r--r-- | arch/x86/kvm/svm/vmenter.S | 9 |
2 files changed, 9 insertions, 7 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 2be5bbae3a40..117bb0b28535 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3330,13 +3330,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) */ x86_spec_ctrl_set_guest(svm->spec_ctrl, svm->virt_spec_ctrl); - local_irq_enable(); - __svm_vcpu_run(svm->vmcb_pa, (unsigned long *)&svm->vcpu.arch.regs); - /* Eliminate branch target predictions from guest mode */ - vmexit_fill_RSB(); - #ifdef CONFIG_X86_64 wrmsrl(MSR_GS_BASE, svm->host.gs_base); #else @@ -3366,8 +3361,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) reload_tss(vcpu); - local_irq_disable(); - x86_spec_ctrl_restore_host(svm->spec_ctrl, svm->virt_spec_ctrl); vcpu->arch.cr2 = svm->vmcb->save.cr2; diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S index fa1af90067e9..723887e35e95 100644 --- a/arch/x86/kvm/svm/vmenter.S +++ b/arch/x86/kvm/svm/vmenter.S @@ -3,6 +3,7 @@ #include <asm/asm.h> #include <asm/bitsperlong.h> #include <asm/kvm_vcpu_regs.h> +#include <asm/nospec-branch.h> #define WORD_SIZE (BITS_PER_LONG / 8) @@ -78,6 +79,7 @@ SYM_FUNC_START(__svm_vcpu_run) pop %_ASM_AX /* Enter guest mode */ + sti 1: vmload %_ASM_AX jmp 3f 2: cmpb $0, kvm_rebooting @@ -99,6 +101,13 @@ SYM_FUNC_START(__svm_vcpu_run) ud2 _ASM_EXTABLE(5b, 6b) 7: + cli + +#ifdef CONFIG_RETPOLINE + /* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */ + FILL_RETURN_BUFFER %_ASM_AX, RSB_CLEAR_LOOPS, X86_FEATURE_RETPOLINE +#endif + /* "POP" @regs to RAX. */ pop %_ASM_AX |