kvm: svm: prepare for new bit definition in nested_ctl

Currently the nested_ctl variable in the vmcb_control_area structure is
used to indicate nested paging support. The nested paging support field
is actually defined as bit 0 of the field. In order to support a new
feature flag the usage of the nested_ctl and nested paging support must
be converted to operate on a single bit.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 78dd9df881577dc1bc1b2bddf84729ff2fe5fd40..c936c9824405c6a917027949aa316486ce967bcd 100644 (file)
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -146,6 +146,8 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
 #define SVM_VM_CR_SVM_LOCK_MASK 0x0008ULL
 #define SVM_VM_CR_SVM_DIS_MASK  0x0010ULL
 
+#define SVM_NESTED_CTL_NP_ENABLE       BIT(0)
+
 struct __attribute__ ((__packed__)) vmcb_seg {
        u16 selector;
        u16 attrib;

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 59e13a79c2e3eea5588be38d3fdb677cf9076b3d..1c8158a6ee06b9d6da94d92b3179e4a6205b6775 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1293,7 +1293,7 @@ static void init_vmcb(struct vcpu_svm *svm)
 
        if (npt_enabled) {
                /* Setup VMCB for Nested Paging */
-               control->nested_ctl = 1;
+               control->nested_ctl |= SVM_NESTED_CTL_NP_ENABLE;
                clr_intercept(svm, INTERCEPT_INVLPG);
                clr_exception_intercept(svm, PF_VECTOR);
                clr_cr_intercept(svm, INTERCEPT_CR3_READ);
@@ -2918,7 +2918,8 @@ static bool nested_vmcb_checks(struct vmcb *vmcb)
        if (vmcb->control.asid == 0)
                return false;
 
-       if (vmcb->control.nested_ctl && !npt_enabled)
+       if ((vmcb->control.nested_ctl & SVM_NESTED_CTL_NP_ENABLE) &&
+           !npt_enabled)
                return false;
 
        return true;
@@ -2932,7 +2933,7 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
        else
                svm->vcpu.arch.hflags &= ~HF_HIF_MASK;
 
-       if (nested_vmcb->control.nested_ctl) {
+       if (nested_vmcb->control.nested_ctl & SVM_NESTED_CTL_NP_ENABLE) {
                kvm_mmu_unload(&svm->vcpu);
                svm->nested.nested_cr3 = nested_vmcb->control.nested_cr3;
                nested_svm_init_mmu_context(&svm->vcpu);