Commit 4438355e authored by Paul Durrant's avatar Paul Durrant Committed by Sean Christopherson
Browse files

KVM: x86/xen: mark guest pages dirty with the pfncache lock held 



Sampling gpa and memslot from an unlocked pfncache may yield inconsistent
values so, since there is no problem with calling mark_page_dirty_in_slot()
with the pfncache lock held, relocate the calls in
kvm_xen_update_runstate_guest() and kvm_xen_inject_pending_events()
accordingly.

Signed-off-by: default avatarPaul Durrant <pdurrant@amazon.com>
Reviewed-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20240215152916.1158-4-paul@xen.org


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 41496fff

arch/x86/kvm/xen.c

+6 −7
Original line number Diff line number Diff line
@@ -452,14 +452,13 @@ static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic) 
		smp_wmb();

	}



	if (user_len2)

	if (user_len2) {

		mark_page_dirty_in_slot(v->kvm, gpc2->memslot, gpc2->gpa >> PAGE_SHIFT);

		read_unlock(&gpc2->lock);



	read_unlock_irqrestore(&gpc1->lock, flags);

	}



	mark_page_dirty_in_slot(v->kvm, gpc1->memslot, gpc1->gpa >> PAGE_SHIFT);

	if (user_len2)

		mark_page_dirty_in_slot(v->kvm, gpc2->memslot, gpc2->gpa >> PAGE_SHIFT);

	read_unlock_irqrestore(&gpc1->lock, flags);

}



void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
@@ -565,13 +564,13 @@ void kvm_xen_inject_pending_events(struct kvm_vcpu *v) 
			     : "0" (evtchn_pending_sel32));

		WRITE_ONCE(vi->evtchn_upcall_pending, 1);

	}



	mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);

	read_unlock_irqrestore(&gpc->lock, flags);



	/* For the per-vCPU lapic vector, deliver it as MSI. */

	if (v->arch.xen.upcall_vector)

		kvm_xen_inject_vcpu_vector(v);



	mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);

}



int __kvm_xen_has_interrupt(struct kvm_vcpu *v)