This is a note to let you know that I've just added the patch titled
x86/cpu: Reinitialize IA32_FEAT_CTL MSR on BSP during wakeup
to the 5.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-cpu-reinitialize-ia32_feat_ctl-msr-on-bsp-during-wakeup.patch
and it can be found in the queue-5.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5d5103595e9e53048bb7e70ee2673c897ab38300 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Date: Mon, 8 Jun 2020 10:41:34 -0700
Subject: x86/cpu: Reinitialize IA32_FEAT_CTL MSR on BSP during wakeup
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
commit 5d5103595e9e53048bb7e70ee2673c897ab38300 upstream.
Reinitialize IA32_FEAT_CTL on the BSP during wakeup to handle the case
where firmware doesn't initialize or save/restore across S3. This fixes
a bug where IA32_FEAT_CTL is left uninitialized and results in VMXON
taking a #GP due to VMX not being fully enabled, i.e. breaks KVM.
Use init_ia32_feat_ctl() to "restore" IA32_FEAT_CTL as it already deals
with the case where the MSR is locked, and because APs already redo
init_ia32_feat_ctl() during suspend by virtue of the SMP boot flow being
used to reinitialize APs upon wakeup. Do the call in the early wakeup
flow to avoid dependencies in the syscore_ops chain, e.g. simply adding
a resume hook is not guaranteed to work, as KVM does VMXON in its own
resume hook, kvm_resume(), when KVM has active guests.
Fixes: 21bd3467a58e ("KVM: VMX: Drop initialization of IA32_FEAT_CTL MSR")
Reported-by: Brad Campbell <lists2009@xxxxxxxxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Liam Merwick <liam.merwick@xxxxxxxxxx>
Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Tested-by: Brad Campbell <lists2009@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v5.6
Link: https://lkml.kernel.org/r/20200608174134.11157-1-sean.j.christopherson@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/cpu.h | 5 +++++
arch/x86/kernel/cpu/centaur.c | 1 +
arch/x86/kernel/cpu/cpu.h | 4 ----
arch/x86/kernel/cpu/zhaoxin.c | 1 +
arch/x86/power/cpu.c | 6 ++++++
5 files changed, 13 insertions(+), 4 deletions(-)
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -58,4 +58,9 @@ static inline bool handle_guest_split_lo
return false;
}
#endif
+#ifdef CONFIG_IA32_FEAT_CTL
+void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
+#else
+static inline void init_ia32_feat_ctl(struct cpuinfo_x86 *c) {}
+#endif
#endif /* _ASM_X86_CPU_H */
--- a/arch/x86/kernel/cpu/centaur.c
+++ b/arch/x86/kernel/cpu/centaur.c
@@ -3,6 +3,7 @@
#include <linux/sched.h>
#include <linux/sched/clock.h>
+#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include <asm/e820/api.h>
#include <asm/mtrr.h>
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -81,8 +81,4 @@ extern void update_srbds_msr(void);
extern u64 x86_read_arch_cap_msr(void);
-#ifdef CONFIG_IA32_FEAT_CTL
-void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
-#endif
-
#endif /* ARCH_X86_CPU_H */
--- a/arch/x86/kernel/cpu/zhaoxin.c
+++ b/arch/x86/kernel/cpu/zhaoxin.c
@@ -2,6 +2,7 @@
#include <linux/sched.h>
#include <linux/sched/clock.h>
+#include <asm/cpu.h>
#include <asm/cpufeature.h>
#include "cpu.h"
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -193,6 +193,8 @@ static void fix_processor_context(void)
*/
static void notrace __restore_processor_state(struct saved_context *ctxt)
{
+ struct cpuinfo_x86 *c;
+
if (ctxt->misc_enable_saved)
wrmsrl(MSR_IA32_MISC_ENABLE, ctxt->misc_enable);
/*
@@ -263,6 +265,10 @@ static void notrace __restore_processor_
mtrr_bp_restore();
perf_restore_debug_store();
msr_restore_context(ctxt);
+
+ c = &cpu_data(smp_processor_id());
+ if (cpu_has(c, X86_FEATURE_MSR_IA32_FEAT_CTL))
+ init_ia32_feat_ctl(c);
}
/* Needed by apm.c */
Patches currently in stable-queue which might be from sean.j.christopherson@xxxxxxxxx are
queue-5.7/x86-cpu-reinitialize-ia32_feat_ctl-msr-on-bsp-during-wakeup.patch
queue-5.7/kvm-nvmx-plumb-l2-gpa-through-to-pml-emulation.patch
queue-5.7/kvm-x86-fix-msr-range-of-apic-registers-in-x2apic-mode.patch
queue-5.7/kvm-vmx-stop-context-switching-msr_ia32_umwait_control.patch
