diff options
| author | Anton Romanov <romanton@google.com> | 2022-02-16 18:26:54 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-16 14:23:40 +0100 |
| commit | bcd4279b989f67e1a25b6dd117bd6ea49e56a528 (patch) | |
| tree | 34674fb64e9ffe6307c212fb177f41ad0b6e87e9 /arch/x86/kvm/x86.c | |
| parent | e160ee96d03ffd239c80fd54f759e87368468349 (diff) | |
kvm: x86: Disable KVM_HC_CLOCK_PAIRING if tsc is in always catchup mode
[ Upstream commit 3a55f729240a686aa8af00af436306c0cd532522 ]
If vcpu has tsc_always_catchup set each request updates pvclock data.
KVM_HC_CLOCK_PAIRING consumers such as ptp_kvm_x86 rely on tsc read on
host's side and do hypercall inside pvclock_read_retry loop leading to
infinite loop in such situation.
v3:
Removed warn
Changed return code to KVM_EFAULT
v2:
Added warn
Signed-off-by: Anton Romanov <romanton@google.com>
Message-Id: <20220216182653.506850-1-romanton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8213f7fb71a7..61bc54748f22 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8666,6 +8666,13 @@ static int kvm_pv_clock_pairing(struct kvm_vcpu *vcpu, gpa_t paddr, if (clock_type != KVM_CLOCK_PAIRING_WALLCLOCK) return -KVM_EOPNOTSUPP; + /* + * When tsc is in permanent catchup mode guests won't be able to use + * pvclock_read_retry loop to get consistent view of pvclock + */ + if (vcpu->arch.tsc_always_catchup) + return -KVM_EOPNOTSUPP; + if (!kvm_get_walltime_and_clockread(&ts, &cycle)) return -KVM_EOPNOTSUPP; |