From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH 2/2] Revert "KVM: x86: zero kvmclock_offset when vcpu0 initializes kvmclock system MSR" Date: Fri, 18 Sep 2015 17:54:30 +0200 Message-ID: <1442591670-5216-3-git-send-email-rkrcmar@redhat.com> References: <1442591670-5216-1-git-send-email-rkrcmar@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kvm@vger.kernel.org, Paolo Bonzini , Marcelo Tosatti , Luiz Capitulino To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1442591670-5216-1-git-send-email-rkrcmar@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Shifting pvclock_vcpu_time_info.system_time on write to KVM system time MSR is a change of ABI. Probably only 2.6.16 based SLES 10 breaks due to its custom enhancements to kvmclock, but KVM never declared the MSR only for one-shot initialization. (Doc says that only one write is needed.) This reverts commit b7e60c5aedd2b63f16ef06fde4f81ca032211bc5. And adds a note to the definition of PVCLOCK_COUNTS_FROM_ZERO. Signed-off-by: Radim Kr=C4=8Dm=C3=A1=C5=99 --- arch/x86/include/asm/pvclock-abi.h | 1 + arch/x86/kvm/x86.c | 4 ---- 2 files changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/x86/include/asm/pvclock-abi.h b/arch/x86/include/asm/= pvclock-abi.h index 655e07a48f6c..67f08230103a 100644 --- a/arch/x86/include/asm/pvclock-abi.h +++ b/arch/x86/include/asm/pvclock-abi.h @@ -41,6 +41,7 @@ struct pvclock_wall_clock { =20 #define PVCLOCK_TSC_STABLE_BIT (1 << 0) #define PVCLOCK_GUEST_STOPPED (1 << 1) +/* PVCLOCK_COUNTS_FROM_ZERO broke ABI and can't be used anymore. */ #define PVCLOCK_COUNTS_FROM_ZERO (1 << 2) #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_PVCLOCK_ABI_H */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 18d59b584dee..34d33f4757d2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1707,8 +1707,6 @@ static int kvm_guest_time_update(struct kvm_vcpu = *v) vcpu->pvclock_set_guest_stopped_request =3D false; } =20 - pvclock_flags |=3D PVCLOCK_COUNTS_FROM_ZERO; - /* If the host uses TSC clocksource, then it is stable */ if (use_master_clock) pvclock_flags |=3D PVCLOCK_TSC_STABLE_BIT; @@ -2006,8 +2004,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, str= uct msr_data *msr_info) &vcpu->requests); =20 ka->boot_vcpu_runs_old_kvmclock =3D tmp; - - ka->kvmclock_offset =3D -get_kernel_ns(); } =20 vcpu->arch.time =3D data; --=20 2.5.2