diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0026-x86-bugs-KVM-Support-the-combination-of-guest-and-ho.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0026-x86-bugs-KVM-Support-the-combination-of-guest-and-ho.patch | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0026-x86-bugs-KVM-Support-the-combination-of-guest-and-ho.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0026-x86-bugs-KVM-Support-the-combination-of-guest-and-ho.patch deleted file mode 100644 index d0e8ddcb..00000000 --- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0026-x86-bugs-KVM-Support-the-combination-of-guest-and-ho.patch +++ /dev/null @@ -1,137 +0,0 @@ -From d9dc73cbf12047f0d0e171366bfb962b3a592e6f Mon Sep 17 00:00:00 2001 -From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> -Date: Wed, 25 Apr 2018 22:04:19 -0400 -Subject: [PATCH 26/93] x86/bugs, KVM: Support the combination of guest and - host IBRS - -commit 5cf687548705412da47c9cec342fd952d71ed3d5 upstream - -A guest may modify the SPEC_CTRL MSR from the value used by the -kernel. Since the kernel doesn't use IBRS, this means a value of zero is -what is needed in the host. - -But the 336996-Speculative-Execution-Side-Channel-Mitigations.pdf refers to -the other bits as reserved so the kernel should respect the boot time -SPEC_CTRL value and use that. - -This allows to deal with future extensions to the SPEC_CTRL interface if -any at all. - -Note: This uses wrmsrl() instead of native_wrmsl(). I does not make any -difference as paravirt will over-write the callq *0xfff.. with the wrmsrl -assembler code. - -Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> -Signed-off-by: Thomas Gleixner <tglx@linutronix.de> -Reviewed-by: Borislav Petkov <bp@suse.de> -Reviewed-by: Ingo Molnar <mingo@kernel.org> -Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> -Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> ---- - arch/x86/include/asm/nospec-branch.h | 10 ++++++++++ - arch/x86/kernel/cpu/bugs.c | 18 ++++++++++++++++++ - arch/x86/kvm/svm.c | 6 ++---- - arch/x86/kvm/vmx.c | 6 ++---- - 4 files changed, 32 insertions(+), 8 deletions(-) - -diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h -index 9ec3d4d..d1c2630 100644 ---- a/arch/x86/include/asm/nospec-branch.h -+++ b/arch/x86/include/asm/nospec-branch.h -@@ -228,6 +228,16 @@ enum spectre_v2_mitigation { - extern void x86_spec_ctrl_set(u64); - extern u64 x86_spec_ctrl_get_default(void); - -+/* -+ * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR -+ * the guest has, while on VMEXIT we restore the host view. This -+ * would be easier if SPEC_CTRL were architecturally maskable or -+ * shadowable for guests but this is not (currently) the case. -+ * Takes the guest view of SPEC_CTRL MSR as a parameter. -+ */ -+extern void x86_spec_ctrl_set_guest(u64); -+extern void x86_spec_ctrl_restore_host(u64); -+ - extern char __indirect_thunk_start[]; - extern char __indirect_thunk_end[]; - -diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c -index 6ff972a..f5cad2f 100644 ---- a/arch/x86/kernel/cpu/bugs.c -+++ b/arch/x86/kernel/cpu/bugs.c -@@ -122,6 +122,24 @@ u64 x86_spec_ctrl_get_default(void) - } - EXPORT_SYMBOL_GPL(x86_spec_ctrl_get_default); - -+void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl) -+{ -+ if (!boot_cpu_has(X86_FEATURE_IBRS)) -+ return; -+ if (x86_spec_ctrl_base != guest_spec_ctrl) -+ wrmsrl(MSR_IA32_SPEC_CTRL, guest_spec_ctrl); -+} -+EXPORT_SYMBOL_GPL(x86_spec_ctrl_set_guest); -+ -+void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl) -+{ -+ if (!boot_cpu_has(X86_FEATURE_IBRS)) -+ return; -+ if (x86_spec_ctrl_base != guest_spec_ctrl) -+ wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); -+} -+EXPORT_SYMBOL_GPL(x86_spec_ctrl_restore_host); -+ - #ifdef RETPOLINE - static bool spectre_v2_bad_module; - -diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c -index 8551a54..a07579f 100644 ---- a/arch/x86/kvm/svm.c -+++ b/arch/x86/kvm/svm.c -@@ -4905,8 +4905,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) - * is no need to worry about the conditional branch over the wrmsr - * being speculatively taken. - */ -- if (svm->spec_ctrl) -- native_wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl); -+ x86_spec_ctrl_set_guest(svm->spec_ctrl); - - asm volatile ( - "push %%" _ASM_BP "; \n\t" -@@ -5018,8 +5017,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) - if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))) - svm->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL); - -- if (svm->spec_ctrl) -- native_wrmsrl(MSR_IA32_SPEC_CTRL, 0); -+ x86_spec_ctrl_restore_host(svm->spec_ctrl); - - /* Eliminate branch target predictions from guest mode */ - vmexit_fill_RSB(); -diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c -index 273313f..c386d13 100644 ---- a/arch/x86/kvm/vmx.c -+++ b/arch/x86/kvm/vmx.c -@@ -8898,8 +8898,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) - * is no need to worry about the conditional branch over the wrmsr - * being speculatively taken. - */ -- if (vmx->spec_ctrl) -- native_wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl); -+ x86_spec_ctrl_set_guest(vmx->spec_ctrl); - - vmx->__launched = vmx->loaded_vmcs->launched; - asm( -@@ -9037,8 +9036,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) - if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))) - vmx->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL); - -- if (vmx->spec_ctrl) -- native_wrmsrl(MSR_IA32_SPEC_CTRL, 0); -+ x86_spec_ctrl_restore_host(vmx->spec_ctrl); - - /* Eliminate branch target predictions from guest mode */ - vmexit_fill_RSB(); --- -2.7.4 - |