Commit 3fa5e8fd authored Jul 26, 2021 by Paolo Bonzini

KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized



Right now, svm_hv_vmcb_dirty_nested_enlightenments has an incorrect
dereference of vmcb->control.reserved_sw before the vmcb is checked
for being non-NULL.  The compiler is usually sinking the dereference
after the check; instead of doing this ourselves in the source,
ensure that svm_hv_vmcb_dirty_nested_enlightenments is only called
with a non-NULL VMCB.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Vineeth Pillai <viremana@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[Untested for now due to issues with my AMD machine. - Paolo]

parent c33e05d9

arch/x86/kvm/svm/svm.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1406,8 +1406,6 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
		goto error_free_vmsa_page;
		}

		svm_vcpu_init_msrpm(vcpu, svm->msrpm);

		svm->vmcb01.ptr = page_address(vmcb01_page);
		svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT);

		@@ -1419,6 +1417,8 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
		svm_switch_vmcb(svm, &svm->vmcb01);
		init_vmcb(vcpu);

		svm_vcpu_init_msrpm(vcpu, svm->msrpm);

		svm_init_osvw(vcpu);
		vcpu->arch.microcode_version = 0x01000065;

arch/x86/kvm/svm/svm_onhyperv.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -89,7 +89,7 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
		* as we mark it dirty unconditionally towards end of vcpu
		* init phase.
		*/
		if (vmcb && vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
		if (vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
		hve->hv_enlightenments_control.msr_bitmap)
		vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
		}