From: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com
mainline inclusion from mainline-v6.8-rc1 commit 1c6d984f523f67ecfad1083bb04c55d91977bb15 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I990A4 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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kvm_guest_cpu_offline() tries to disable kvmclock regardless if it is present in the VM. It leads to write to a MSR that doesn't exist on some configurations, namely in TDX guest:
unchecked MSR access error: WRMSR to 0x12 (tried to write 0x0000000000000000) at rIP: 0xffffffff8110687c (kvmclock_disable+0x1c/0x30)
kvmclock enabling is gated by CLOCKSOURCE and CLOCKSOURCE2 KVM paravirt features.
Do not disable kvmclock if it was not enabled.
Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Fixes: c02027b5742b ("x86/kvm: Disable kvmclock on all CPUs on shutdown") Reviewed-by: Sean Christopherson seanjc@google.com Reviewed-by: Vitaly Kuznetsov vkuznets@redhat.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Wanpeng Li wanpengli@tencent.com Cc: stable@vger.kernel.org Message-Id: 20231205004510.27164-6-kirill.shutemov@linux.intel.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: liwei liwei728@huawei.com --- arch/x86/kernel/kvmclock.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index d1672a2b1203..0c7a77889f63 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -38,8 +38,8 @@
static int kvmclock __initdata = 1; static int kvmclock_vsyscall __initdata = 1; -static int msr_kvm_system_time __ro_after_init = MSR_KVM_SYSTEM_TIME; -static int msr_kvm_wall_clock __ro_after_init = MSR_KVM_WALL_CLOCK; +static int msr_kvm_system_time __ro_after_init; +static int msr_kvm_wall_clock __ro_after_init; static u64 kvm_sched_clock_offset __ro_after_init;
static int __init parse_no_kvmclock(char *arg) @@ -229,7 +229,8 @@ static void kvm_crash_shutdown(struct pt_regs *regs)
void kvmclock_disable(void) { - native_write_msr(msr_kvm_system_time, 0, 0); + if (msr_kvm_system_time) + native_write_msr(msr_kvm_system_time, 0, 0); }
static void __init kvmclock_init_mem(void) @@ -326,7 +327,10 @@ void __init kvmclock_init(void) if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW; msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW; - } else if (!kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) { + } else if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) { + msr_kvm_system_time = MSR_KVM_SYSTEM_TIME; + msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK; + } else { return; }