From: Paul Durrant pdurrant@amazon.com
A subsequent patch will allow shared_info to be initialized using either a GPA or a user-space (i.e. VMM) HVA. To make that patch cleaner, separate the initialization of the shared_info content from the activation of the pfncache.
Signed-off-by: Paul Durrant pdurrant@amazon.com Reviewed-by: David Woodhouse dwmw@amazon.co.uk --- Cc: Sean Christopherson seanjc@google.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@redhat.com Cc: Borislav Petkov bp@alien8.de Cc: Dave Hansen dave.hansen@linux.intel.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: David Woodhouse dwmw2@infradead.org Cc: x86@kernel.org
v11: - Fix accidental regression from commit 5d6d6a7d7e66a ("KVM: x86: Refine calculation of guest wall clock to use a single TSC read").
v10: - New in this version. --- arch/x86/kvm/xen.c | 55 +++++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 23 deletions(-)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index f9b1e494c430..df53fea73747 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -34,41 +34,32 @@ static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r);
DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
-static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn) +static int kvm_xen_shared_info_init(struct kvm *kvm) { struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache; struct pvclock_wall_clock *wc; - gpa_t gpa = gfn_to_gpa(gfn); u32 *wc_sec_hi; u32 wc_version; u64 wall_nsec; int ret = 0; int idx = srcu_read_lock(&kvm->srcu);
- if (gfn == KVM_XEN_INVALID_GFN) { - kvm_gpc_deactivate(gpc); - goto out; - } + read_lock_irq(&gpc->lock); + while (!kvm_gpc_check(gpc, PAGE_SIZE)) { + read_unlock_irq(&gpc->lock);
- do { - ret = kvm_gpc_activate(gpc, gpa, PAGE_SIZE); + ret = kvm_gpc_refresh(gpc, PAGE_SIZE); if (ret) goto out;
- /* - * This code mirrors kvm_write_wall_clock() except that it writes - * directly through the pfn cache and doesn't mark the page dirty. - */ - wall_nsec = kvm_get_wall_clock_epoch(kvm); - - /* It could be invalid again already, so we need to check */ read_lock_irq(&gpc->lock); + }
- if (gpc->valid) - break; - - read_unlock_irq(&gpc->lock); - } while (1); + /* + * This code mirrors kvm_write_wall_clock() except that it writes + * directly through the pfn cache and doesn't mark the page dirty. + */ + wall_nsec = kvm_get_wall_clock_epoch(kvm);
/* Paranoia checks on the 32-bit struct layout */ BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900); @@ -639,12 +630,30 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data) } break;
- case KVM_XEN_ATTR_TYPE_SHARED_INFO: + case KVM_XEN_ATTR_TYPE_SHARED_INFO: { + int idx; + mutex_lock(&kvm->arch.xen.xen_lock); - r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn); + + idx = srcu_read_lock(&kvm->srcu); + + if (data->u.shared_info.gfn == KVM_XEN_INVALID_GFN) { + kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache); + r = 0; + } else { + r = kvm_gpc_activate(&kvm->arch.xen.shinfo_cache, + gfn_to_gpa(data->u.shared_info.gfn), + PAGE_SIZE); + } + + srcu_read_unlock(&kvm->srcu, idx); + + if (!r && kvm->arch.xen.shinfo_cache.active) + r = kvm_xen_shared_info_init(kvm); + mutex_unlock(&kvm->arch.xen.xen_lock); break; - + } case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR: if (data->u.vector && data->u.vector < 0x10) r = -EINVAL;