diff mbox series

[v3,1/6] KVM: x86: Introduce KVM_REQ_RING_SOFT_FULL

Message ID 20220922003214.276736-2-gshan@redhat.com (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: Enable ring-based dirty memory tracking | expand

Commit Message

Gavin Shan Sept. 22, 2022, 12:32 a.m. UTC 
This adds KVM_REQ_RING_SOFT_FULL, which is raised when the dirty
ring of the specific VCPU becomes softly full in kvm_dirty_ring_push().
The VCPU is enforced to exit when the request is raised and its
dirty ring is softly full on its entrance.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 arch/x86/kvm/x86.c       | 19 ++++++++++---------
 include/linux/kvm_host.h |  1 +
 virt/kvm/dirty_ring.c    |  4 ++++
 3 files changed, 15 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 43a6a7efc6ec..18a4da71989e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10264,16 +10264,17 @@  static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
 	bool req_immediate_exit = false;
 
-	/* Forbid vmenter if vcpu dirty ring is soft-full */
-	if (unlikely(vcpu->kvm->dirty_ring_size &&
-		     kvm_dirty_ring_soft_full(&vcpu->dirty_ring))) {
-		vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL;
-		trace_kvm_dirty_ring_exit(vcpu);
-		r = 0;
-		goto out;
-	}
-
 	if (kvm_request_pending(vcpu)) {
+		/* Forbid vmenter if vcpu dirty ring is soft-full */
+		if (kvm_check_request(KVM_REQ_RING_SOFT_FULL, vcpu) &&
+		    kvm_dirty_ring_soft_full(&vcpu->dirty_ring)) {
+			kvm_make_request(KVM_REQ_RING_SOFT_FULL, vcpu);
+			vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL;
+			trace_kvm_dirty_ring_exit(vcpu);
+			r = 0;
+			goto out;
+		}
+
 		if (kvm_check_request(KVM_REQ_VM_DEAD, vcpu)) {
 			r = -EIO;
 			goto out;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f4519d3689e1..53fa3134fee0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -157,6 +157,7 @@  static inline bool is_error_page(struct page *page)
 #define KVM_REQ_VM_DEAD           (1 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
 #define KVM_REQ_UNBLOCK           2
 #define KVM_REQ_UNHALT            3
+#define KVM_REQ_RING_SOFT_FULL    4
 #define KVM_REQUEST_ARCH_BASE     8
 
 /*
diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
index f4c2a6eb1666..f0e49937bc9e 100644
--- a/virt/kvm/dirty_ring.c
+++ b/virt/kvm/dirty_ring.c
@@ -149,6 +149,7 @@  int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring)
 
 void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset)
 {
+	struct kvm_vcpu *vcpu = container_of(ring, struct kvm_vcpu, dirty_ring);
 	struct kvm_dirty_gfn *entry;
 
 	/* It should never get full */
@@ -166,6 +167,9 @@  void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset)
 	kvm_dirty_gfn_set_dirtied(entry);
 	ring->dirty_index++;
 	trace_kvm_dirty_ring_push(ring, slot, offset);
+
+	if (kvm_dirty_ring_soft_full(ring))
+		kvm_make_request(KVM_REQ_RING_SOFT_FULL, vcpu);
 }
 
 struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset)