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 enumerated or disabled by user
from kernel command line.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Fixes: c02027b5742b ("x86/kvm: Disable kvmclock on all CPUs on shutdown")
---
arch/x86/kernel/kvmclock.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index fb8f52149be9..cba2e732e53f 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -22,7 +22,7 @@
#include <asm/x86_init.h>
#include <asm/kvmclock.h>
-static int kvmclock __initdata = 1;
+static int kvmclock __ro_after_init = 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;
@@ -195,7 +195,12 @@ static void kvm_setup_secondary_clock(void)
void kvmclock_disable(void)
{
- native_write_msr(msr_kvm_system_time, 0, 0);
+ if (!kvm_para_available() || !kvmclock)
+ return;
+
+ if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE) ||
+ kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2))
+ native_write_msr(msr_kvm_system_time, 0, 0);
}
static void __init kvmclock_init_mem(void)
--
2.41.0
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