commit
0f923e07124df069ba68d8bb12324398f4b6b709 upstream.
* Invert the mask of bits that we pick from L2 in
nested_vmcb02_prepare_control
* Invert and explicitly use VIRQ related bits bitmask in svm_clear_vintr
This fixes a security issue that allowed a malicious L1 to run L2 with
AVIC enabled, which allowed the L2 to exploit the uninitialized and enabled
AVIC to read/write the host physical memory at some offsets.
Fixes:
3d6368ef580a ("KVM: SVM: Add VMRUN handler")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
#define V_IGN_TPR_SHIFT 20
#define V_IGN_TPR_MASK (1 << V_IGN_TPR_SHIFT)
+#define V_IRQ_INJECTION_BITS_MASK (V_IRQ_MASK | V_INTR_PRIO_MASK | V_IGN_TPR_MASK)
+
#define V_INTR_MASKING_SHIFT 24
#define V_INTR_MASKING_MASK (1 << V_INTR_MASKING_SHIFT)
static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
{
- const u32 mask = V_INTR_MASKING_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK;
+ const u32 int_ctl_vmcb01_bits =
+ V_INTR_MASKING_MASK | V_GIF_MASK | V_GIF_ENABLE_MASK;
+
+ const u32 int_ctl_vmcb12_bits = V_TPR_MASK | V_IRQ_INJECTION_BITS_MASK;
if (nested_npt_enabled(svm))
nested_svm_init_mmu_context(&svm->vcpu);
svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset =
svm->vcpu.arch.l1_tsc_offset + svm->nested.ctl.tsc_offset;
- svm->vmcb->control.int_ctl =
- (svm->nested.ctl.int_ctl & ~mask) |
- (svm->nested.hsave->control.int_ctl & mask);
+ svm->vmcb->control.int_ctl =
+ (svm->nested.ctl.int_ctl & int_ctl_vmcb12_bits) |
+ (svm->nested.hsave->control.int_ctl & int_ctl_vmcb01_bits);
svm->vmcb->control.virt_ext = svm->nested.ctl.virt_ext;
svm->vmcb->control.int_vector = svm->nested.ctl.int_vector;
static void svm_clear_vintr(struct vcpu_svm *svm)
{
- const u32 mask = V_TPR_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK | V_INTR_MASKING_MASK;
svm_clr_intercept(svm, INTERCEPT_VINTR);
/* Drop int_ctl fields related to VINTR injection. */
- svm->vmcb->control.int_ctl &= mask;
+ svm->vmcb->control.int_ctl &= ~V_IRQ_INJECTION_BITS_MASK;
if (is_guest_mode(&svm->vcpu)) {
- svm->nested.hsave->control.int_ctl &= mask;
+ svm->nested.hsave->control.int_ctl &= ~V_IRQ_INJECTION_BITS_MASK;
WARN_ON((svm->vmcb->control.int_ctl & V_TPR_MASK) !=
(svm->nested.ctl.int_ctl & V_TPR_MASK));
- svm->vmcb->control.int_ctl |= svm->nested.ctl.int_ctl & ~mask;
+ svm->vmcb->control.int_ctl |= svm->nested.ctl.int_ctl &
+ V_IRQ_INJECTION_BITS_MASK;
}
vmcb_mark_dirty(svm->vmcb, VMCB_INTR);