linux-kernel - [PATCH 1/3] KVM: x86: Fully re-initialize supported_vm

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Message-ID: <20240423165328.2853870-2-seanjc@google.com>
Date: Tue, 23 Apr 2024 09:53:26 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] KVM: x86: Fully re-initialize supported_vm_types on
 vendor module load

Recompute the entire set of supported VM types when a vendor module is
loaded, as preserving supported_vm_types across vendor module unload and
reload can result in VM types being incorrectly treated as supported.

E.g. if a vendor module is loaded with TDP enabled, unloaded, and then
reloaded with TDP disabled, KVM_X86_SW_PROTECTED_VM will be incorrectly
retained.  Ditto for SEV_VM and SEV_ES_VM and their respective module
params in kvm-amd.ko.

Fixes: 2a955c4db1dd ("KVM: x86: Add supported_vm_types to kvm_caps")
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/x86.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2d2619d3eee4..a65a1012d878 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -94,7 +94,6 @@
 
 struct kvm_caps kvm_caps __read_mostly = {
 	.supported_mce_cap = MCG_CTL_P | MCG_SER_P,
-	.supported_vm_types = BIT(KVM_X86_DEFAULT_VM),
 };
 EXPORT_SYMBOL_GPL(kvm_caps);
 
@@ -9776,6 +9775,8 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 	if (r)
 		goto out_free_percpu;
 
+	kvm_caps.supported_vm_types = BIT(KVM_X86_DEFAULT_VM);
+
 	if (boot_cpu_has(X86_FEATURE_XSAVE)) {
 		host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
 		kvm_caps.supported_xcr0 = host_xcr0 & KVM_SUPPORTED_XCR0;
-- 
2.44.0.769.g3c40516874-goog