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| author | Thomas Gleixner <tglx@linutronix.de> | 2018-05-11 15:21:01 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-05-17 17:09:16 +0200 |
| commit | 15e6c22fd8e5a42c5ed6d487b7c9fe44c2517765 (patch) | |
| tree | a672809b542f900bddd85d7a3deea581913ebe58 | |
| parent | 5f2b745f5e1304f438f9b2cd03ebc8120b6e0d3b (diff) | |
| download | linux-berlin-15e6c22fd8e5a42c5ed6d487b7c9fe44c2517765.tar.gz | |
KVM: SVM: Move spec control call after restore of GS
svm_vcpu_run() invokes x86_spec_ctrl_restore_host() after VMEXIT, but
before the host GS is restored. x86_spec_ctrl_restore_host() uses 'current'
to determine the host SSBD state of the thread. 'current' is GS based, but
host GS is not yet restored and the access causes a triple fault.
Move the call after the host GS restore.
Fixes: 885f82bfbc6f x86/process: Allow runtime control of Speculative Store Bypass
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/svm.c | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 437c1b3711291..fa891c8af842d 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -5651,6 +5651,18 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) #endif ); + /* Eliminate branch target predictions from guest mode */ + vmexit_fill_RSB(); + +#ifdef CONFIG_X86_64 + wrmsrl(MSR_GS_BASE, svm->host.gs_base); +#else + loadsegment(fs, svm->host.fs); +#ifndef CONFIG_X86_32_LAZY_GS + loadsegment(gs, svm->host.gs); +#endif +#endif + /* * We do not use IBRS in the kernel. If this vCPU has used the * SPEC_CTRL MSR it may have left it on; save the value and @@ -5671,18 +5683,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) x86_spec_ctrl_restore_host(svm->spec_ctrl); - /* Eliminate branch target predictions from guest mode */ - vmexit_fill_RSB(); - -#ifdef CONFIG_X86_64 - wrmsrl(MSR_GS_BASE, svm->host.gs_base); -#else - loadsegment(fs, svm->host.fs); -#ifndef CONFIG_X86_32_LAZY_GS - loadsegment(gs, svm->host.gs); -#endif -#endif - reload_tss(vcpu); local_irq_disable(); |