From 69d413cfcf77920bb4d7c4bbfbf305781fa53a0e Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Thu, 3 Mar 2022 15:41:16 +0000 Subject: [PATCH] KVM: x86/xen: Use gfn_to_pfn_cache for vcpu_time_info This switches the final pvclock to kvm_setup_pvclock_pfncache() and now the old kvm_setup_pvclock_page() can be removed. Signed-off-by: David Woodhouse Signed-off-by: Paolo Bonzini Message-Id: <20220303154127.202856-7-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 3 +- arch/x86/kvm/x86.c | 63 ++------------------------------- arch/x86/kvm/xen.c | 21 +++++------ 3 files changed, 11 insertions(+), 76 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index fce4dca16e5b..7808491ebba8 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -606,9 +606,8 @@ struct kvm_vcpu_hv { struct kvm_vcpu_xen { u64 hypercall_rip; u32 current_runstate; - bool vcpu_time_info_set; struct gfn_to_pfn_cache vcpu_info_cache; - struct gfn_to_hva_cache vcpu_time_info_cache; + struct gfn_to_pfn_cache vcpu_time_info_cache; struct gfn_to_pfn_cache runstate_cache; u64 last_steal; u64 runstate_entry_time; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d67487efdba2..feefa1fb32eb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3011,65 +3011,6 @@ static void kvm_setup_guest_pvclock(struct kvm_vcpu *v, trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock); } -static void kvm_setup_pvclock_page(struct kvm_vcpu *v, - struct gfn_to_hva_cache *cache, - unsigned int offset) -{ - struct kvm_vcpu_arch *vcpu = &v->arch; - struct pvclock_vcpu_time_info guest_hv_clock; - - if (unlikely(kvm_read_guest_offset_cached(v->kvm, cache, - &guest_hv_clock, offset, sizeof(guest_hv_clock)))) - return; - - /* This VCPU is paused, but it's legal for a guest to read another - * VCPU's kvmclock, so we really have to follow the specification where - * it says that version is odd if data is being modified, and even after - * it is consistent. - * - * Version field updates must be kept separate. This is because - * kvm_write_guest_cached might use a "rep movs" instruction, and - * writes within a string instruction are weakly ordered. So there - * are three writes overall. - * - * As a small optimization, only write the version field in the first - * and third write. The vcpu->pv_time cache is still valid, because the - * version field is the first in the struct. - */ - BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0); - - if (guest_hv_clock.version & 1) - ++guest_hv_clock.version; /* first time write, random junk */ - - vcpu->hv_clock.version = guest_hv_clock.version + 1; - kvm_write_guest_offset_cached(v->kvm, cache, - &vcpu->hv_clock, offset, - sizeof(vcpu->hv_clock.version)); - - smp_wmb(); - - /* retain PVCLOCK_GUEST_STOPPED if set in guest copy */ - vcpu->hv_clock.flags |= (guest_hv_clock.flags & PVCLOCK_GUEST_STOPPED); - - if (vcpu->pvclock_set_guest_stopped_request) { - vcpu->hv_clock.flags |= PVCLOCK_GUEST_STOPPED; - vcpu->pvclock_set_guest_stopped_request = false; - } - - trace_kvm_pvclock_update(v->vcpu_id, &vcpu->hv_clock); - - kvm_write_guest_offset_cached(v->kvm, cache, - &vcpu->hv_clock, offset, - sizeof(vcpu->hv_clock)); - - smp_wmb(); - - vcpu->hv_clock.version++; - kvm_write_guest_offset_cached(v->kvm, cache, - &vcpu->hv_clock, offset, - sizeof(vcpu->hv_clock.version)); -} - static int kvm_guest_time_update(struct kvm_vcpu *v) { unsigned long flags, tgt_tsc_khz; @@ -3161,8 +3102,8 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) if (vcpu->xen.vcpu_info_cache.active) kvm_setup_guest_pvclock(v, &vcpu->xen.vcpu_info_cache, offsetof(struct compat_vcpu_info, time)); - if (vcpu->xen.vcpu_time_info_set) - kvm_setup_pvclock_page(v, &vcpu->xen.vcpu_time_info_cache, 0); + if (vcpu->xen.vcpu_time_info_cache.active) + kvm_setup_guest_pvclock(v, &vcpu->xen.vcpu_time_info_cache, 0); if (!v->vcpu_idx) kvm_hv_setup_tsc_page(v->kvm, &vcpu->hv_clock); return 0; diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 56e8a6980b65..65ffba89441a 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -463,25 +463,18 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO: if (data->u.gpa == GPA_INVALID) { - vcpu->arch.xen.vcpu_time_info_set = false; + kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, + &vcpu->arch.xen.vcpu_time_info_cache); r = 0; break; } - /* It must fit within a single page */ - if ((data->u.gpa & ~PAGE_MASK) + sizeof(struct pvclock_vcpu_time_info) > PAGE_SIZE) { - r = -EINVAL; - break; - } - - r = kvm_gfn_to_hva_cache_init(vcpu->kvm, + r = kvm_gfn_to_pfn_cache_init(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache, - data->u.gpa, + NULL, KVM_HOST_USES_PFN, data->u.gpa, sizeof(struct pvclock_vcpu_time_info)); - if (!r) { - vcpu->arch.xen.vcpu_time_info_set = true; + if (!r) kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); - } break; case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: @@ -622,7 +615,7 @@ int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) break; case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO: - if (vcpu->arch.xen.vcpu_time_info_set) + if (vcpu->arch.xen.vcpu_time_info_cache.active) data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa; else data->u.gpa = GPA_INVALID; @@ -1066,4 +1059,6 @@ void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu) &vcpu->arch.xen.runstate_cache); kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache); + kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, + &vcpu->arch.xen.vcpu_time_info_cache); } -- GitLab