From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
kvm_mmu_unload() destroys all the PGD caches. Use the lighter
kvm_mmu_sync_roots() and kvm_mmu_sync_prev_roots() instead.
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.h | 1 +
arch/x86/kvm/mmu/mmu.c | 16 ++++++++++++++++
arch/x86/kvm/x86.c | 11 +++++------
3 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 1ae70efedcf4..8e9dd63b68a9 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -79,6 +79,7 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
int kvm_mmu_load(struct kvm_vcpu *vcpu);
void kvm_mmu_unload(struct kvm_vcpu *vcpu);
void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);
+void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu);
static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
{
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 900c7a157c99..fb45eeb8dd22 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3634,6 +3634,9 @@ static bool is_unsync_root(hpa_t root)
{
struct kvm_mmu_page *sp;
+ if (!VALID_PAGE(root))
+ return false;
+
/*
* Even if another CPU was marking the SP as unsync-ed simultaneously,
* any guest page table changes are not guaranteed to be visible anyway
@@ -3706,6 +3709,19 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
write_unlock(&vcpu->kvm->mmu_lock);
}
+void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu)
+{
+ unsigned long roots_to_free = 0;
+ int i;
+
+ for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
+ if (is_unsync_root(vcpu->arch.mmu->prev_roots[i].hpa))
+ roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
+
+ /* sync prev_roots by simply freeing them */
+ kvm_mmu_free_roots(vcpu, vcpu->arch.mmu, roots_to_free);
+}
+
static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gpa_t vaddr,
u32 access, struct x86_exception *exception)
{
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 13df3ca88e09..1771cd4bb449 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3251,15 +3251,14 @@ static void kvm_vcpu_flush_tlb_guest(struct kvm_vcpu *vcpu)
++vcpu->stat.tlb_flush;
if (!tdp_enabled) {
- /*
+ /*
* A TLB flush on behalf of the guest is equivalent to
* INVPCID(all), toggling CR4.PGE, etc., which requires
- * a forced sync of the shadow page tables. Unload the
- * entire MMU here and the subsequent load will sync the
- * shadow page tables, and also flush the TLB.
+ * a forced sync of the shadow page tables. Ensure all the
+ * roots are synced and the guest TLB in hardware is clean.
*/
- kvm_mmu_unload(vcpu);
- return;
+ kvm_mmu_sync_roots(vcpu);
+ kvm_mmu_sync_prev_roots(vcpu);
}
static_call(kvm_x86_tlb_flush_guest)(vcpu);
--
2.19.1.6.gb485710b
