Merge tag 'kvm-x86-fixes-6.10-rcN' of https://github.com/kvm-x86/linux into HEAD

KVM fixes for 6.10

 - Fix a "shift too big" goof in the KVM_SEV_INIT2 selftest.

 - Compute the max mappable gfn for KVM selftests on x86 using GuestMaxPhyAddr
   from KVM's supported CPUID (if it's available).

 - Fix a race in kvm_vcpu_on_spin() by ensuring loads and stores are atomic.

 - Fix technically benign bug in __kvm_handle_hva_range() where KVM consumes
   the return from a void-returning function as if it were a boolean.

1 files changed, 5 insertions, 3 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8e422c2c9450..1192942aef91 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -651,7 +651,7 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
 					range->on_lock(kvm);
 
 				if (IS_KVM_NULL_FN(range->handler))
-					break;
+					goto mmu_unlock;
 			}
 			r.ret |= range->handler(kvm, &gfn_range);
 		}
@@ -660,6 +660,7 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
 	if (range->flush_on_ret && r.ret)
 		kvm_flush_remote_tlbs(kvm);
 
+mmu_unlock:
 	if (r.found_memslot)
 		KVM_MMU_UNLOCK(kvm);
 
@@ -4025,12 +4026,13 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
 {
 	struct kvm *kvm = me->kvm;
 	struct kvm_vcpu *vcpu;
-	int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
+	int last_boosted_vcpu;
 	unsigned long i;
 	int yielded = 0;
 	int try = 3;
 	int pass;
 
+	last_boosted_vcpu = READ_ONCE(kvm->last_boosted_vcpu);
 	kvm_vcpu_set_in_spin_loop(me, true);
 	/*
 	 * We boost the priority of a VCPU that is runnable but not
@@ -4068,7 +4070,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
 
 			yielded = kvm_vcpu_yield_to(vcpu);
 			if (yielded > 0) {
-				kvm->last_boosted_vcpu = i;
+				WRITE_ONCE(kvm->last_boosted_vcpu, i);
 				break;
 			} else if (yielded < 0) {
 				try--;