From: Radim Krčmář Date: Fri, 18 Sep 2015 15:54:30 +0000 (+0200) Subject: Revert "KVM: x86: zero kvmclock_offset when vcpu0 initializes kvmclock system MSR" X-Git-Tag: v4.3-rc4~19^2~6 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9bac175d8ed0b1dd3d3611c0713666b724eeace3;p=profile%2Fcommon%2Fplatform%2Fkernel%2Flinux-artik7.git Revert "KVM: x86: zero kvmclock_offset when vcpu0 initializes kvmclock system MSR" 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 Krčmář Acked-by: Marcelo Tosatti Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/include/asm/pvclock-abi.h b/arch/x86/include/asm/pvclock-abi.h index 655e07a..67f0823 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 { #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 991466b..92511d4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1708,8 +1708,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) vcpu->pvclock_set_guest_stopped_request = false; } - pvclock_flags |= PVCLOCK_COUNTS_FROM_ZERO; - /* If the host uses TSC clocksource, then it is stable */ if (use_master_clock) pvclock_flags |= PVCLOCK_TSC_STABLE_BIT; @@ -2007,8 +2005,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) &vcpu->requests); ka->boot_vcpu_runs_old_kvmclock = tmp; - - ka->kvmclock_offset = -get_kernel_ns(); } vcpu->arch.time = data;