diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0062-KVM-SVM-Move-spec-control-call-after-restore-of-GS.patch')
-rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0062-KVM-SVM-Move-spec-control-call-after-restore-of-GS.patch | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0062-KVM-SVM-Move-spec-control-call-after-restore-of-GS.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0062-KVM-SVM-Move-spec-control-call-after-restore-of-GS.patch new file mode 100644 index 00000000..75caec43 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0062-KVM-SVM-Move-spec-control-call-after-restore-of-GS.patch @@ -0,0 +1,70 @@ +From 21d2555ad333e693fc6859bff2a60b9b24de8d99 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Fri, 11 May 2018 15:21:01 +0200 +Subject: [PATCH 62/93] KVM: SVM: Move spec control call after restore of GS + +commit 15e6c22fd8e5a42c5ed6d487b7c9fe44c2517765 upstream + +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> +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kvm/svm.c | 24 ++++++++++++------------ + 1 file changed, 12 insertions(+), 12 deletions(-) + +diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c +index 47779f5..9991462 100644 +--- a/arch/x86/kvm/svm.c ++++ b/arch/x86/kvm/svm.c +@@ -4999,6 +4999,18 @@ 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 +@@ -5019,18 +5031,6 @@ 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(); +-- +2.7.4 + |