lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 20 Sep 2021 18:41:54 +0200 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Zelin Deng <zelin.deng@...ux.alibaba.com>, Paolo Bonzini <pbonzini@...hat.com> Subject: [PATCH 4.14 093/217] KVM: x86: Update vCPUs hv_clock before back to guest when tsc_offset is adjusted From: Zelin Deng <zelin.deng@...ux.alibaba.com> commit d9130a2dfdd4b21736c91b818f87dbc0ccd1e757 upstream. When MSR_IA32_TSC_ADJUST is written by guest due to TSC ADJUST feature especially there's a big tsc warp (like a new vCPU is hot-added into VM which has been up for a long time), tsc_offset is added by a large value then go back to guest. This causes system time jump as tsc_timestamp is not adjusted in the meantime and pvclock monotonic character. To fix this, just notify kvm to update vCPU's guest time before back to guest. Cc: stable@...r.kernel.org Signed-off-by: Zelin Deng <zelin.deng@...ux.alibaba.com> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com> Message-Id: <1619576521-81399-2-git-send-email-zelin.deng@...ux.alibaba.com> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2355,6 +2355,10 @@ int kvm_set_msr_common(struct kvm_vcpu * if (!msr_info->host_initiated) { s64 adj = data - vcpu->arch.ia32_tsc_adjust_msr; adjust_tsc_offset_guest(vcpu, adj); + /* Before back to guest, tsc_timestamp must be adjusted + * as well, otherwise guest's percpu pvclock time could jump. + */ + kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); } vcpu->arch.ia32_tsc_adjust_msr = data; }
Powered by blists - more mailing lists