Commit 4d29de5a authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Ma Wupeng
Browse files

x86/kvm: Do not try to disable kvmclock if it was not enabled 

stable inclusion
from stable-v6.6.14
commit db448ac982e43cb4ce8d0995f26fc46388e01760
bugzilla: https://gitee.com/openeuler/kernel/issues/I99TJK

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=db448ac982e43cb4ce8d0995f26fc46388e01760



--------------------------------

commit 1c6d984f523f67ecfad1083bb04c55d91977bb15 upstream.

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: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: c02027b5 ("x86/kvm: Disable kvmclock on all CPUs on shutdown")
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarVitaly 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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent 61d2cfd9

arch/x86/kernel/kvmclock.c

+8 −4
Original line number Diff line number Diff line
@@ -24,8 +24,8 @@ 


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)
@@ -195,6 +195,7 @@ static void kvm_setup_secondary_clock(void) 


void kvmclock_disable(void)

{

	if (msr_kvm_system_time)

		native_write_msr(msr_kvm_system_time, 0, 0);

}
@@ -294,7 +295,10 @@ 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;

	}