From df06dae3f2a8bfb83683abf88d3dcde23fc8093d Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Feb 2022 16:53:02 +0000 Subject: KVM: Don't actually set a request when evicting vCPUs for GFN cache invd Don't actually set a request bit in vcpu->requests when making a request purely to force a vCPU to exit the guest. Logging a request but not actually consuming it would cause the vCPU to get stuck in an infinite loop during KVM_RUN because KVM would see the pending request and bail from VM-Enter to service the request. Note, it's currently impossible for KVM to set KVM_REQ_GPC_INVALIDATE as nothing in KVM is wired up to set guest_uses_pa=true. But, it'd be all too easy for arch code to introduce use of kvm_gfn_to_pfn_cache_init() without implementing handling of the request, especially since getting test coverage of MMU notifier interaction with specific KVM features usually requires a directed test. Opportunistically rename gfn_to_pfn_cache_invalidate_start()'s wake_vcpus to evict_vcpus. The purpose of the request is to get vCPUs out of guest mode, it's supposed to _avoid_ waking vCPUs that are blocking. Opportunistically rename KVM_REQ_GPC_INVALIDATE to be more specific as to what it wants to accomplish, and to genericize the name so that it can used for similar but unrelated scenarios, should they arise in the future. Add a comment and documentation to explain why the "no action" request exists. Add compile-time assertions to help detect improper usage. Use the inner assertless helper in the one s390 path that makes requests without a hardcoded request. Cc: David Woodhouse Signed-off-by: Sean Christopherson Message-Id: <20220223165302.3205276-1-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/s390/kvm/kvm-s390.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index ca96f84db2cc..91c0cefc94aa 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -3463,7 +3463,7 @@ void exit_sie(struct kvm_vcpu *vcpu) /* Kick a guest cpu out of SIE to process a request synchronously */ void kvm_s390_sync_request(int req, struct kvm_vcpu *vcpu) { - kvm_make_request(req, vcpu); + __kvm_make_request(req, vcpu); kvm_s390_vcpu_request(vcpu); } -- cgit v1.2.3