[PATCH v2 2/7] KVM: x86: Invoke kvm_mmu_unload() directly on CR4.PCIDE change

From: Sean Christopherson
Date: Fri Feb 25 2022 - 13:23:06 EST


Replace a KVM_REQ_MMU_RELOAD request with a direct kvm_mmu_unload() call
when the guest's CR4.PCIDE changes. This will allow tweaking the logic
of KVM_REQ_MMU_RELOAD to free only obsolete/invalid roots, which is the
historical intent of KVM_REQ_MMU_RELOAD. The recent PCIDE behavior is
the only user of KVM_REQ_MMU_RELOAD that doesn't mark affected roots as
obsolete, needs to unconditionally unload the entire MMU, _and_ affects
only the current vCPU.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2157284d05b0..579b26ffc124 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1077,7 +1077,7 @@ void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned lon
*/
if (!tdp_enabled &&
(cr4 & X86_CR4_PCIDE) && !(old_cr4 & X86_CR4_PCIDE))
- kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
+ kvm_mmu_unload(vcpu);

/*
* The TLB has to be flushed for all PCIDs if any of the following
--
2.35.1.574.g5d30c73bfb-goog