[PATCHv4 09/11] KVM: SVM: Add VNMI bit definition

Santosh Shukla
2023-02-27T08:53:37Z

VNMI exposes 3 capability bits (V_NMI, V_NMI_MASK, and V_NMI_ENABLE) to
virtualize NMI and NMI_MASK, Those capability bits are part of
VMCB::intr_ctrl -
V_NMI_PENDING_MASK(11) - Indicates whether a virtual NMI is pending in the
guest.
V_NMI_BLOCKING_MASK(12) - Indicates whether virtual NMI is masked in the
guest.
V_NMI_ENABLE_MASK(26) - Enables the NMI virtualization feature for the
guest.

When Hypervisor wants to inject NMI, it will set V_NMI bit, Processor
will clear the V_NMI bit and Set the V_NMI_MASK which means the Guest is
handling NMI, After the guest handled the NMI, The processor will clear
the V_NMI_MASK on the successful completion of IRET instruction Or if
VMEXIT occurs while delivering the virtual NMI.

To enable the VNMI capability, Hypervisor need to program
V_NMI_ENABLE_MASK bit 1.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
---
v3:
- Renamed V_NMI bits per Sean's v2 comment for
better readability.
https://lore.kernel.org/all/66f93354-22b1-a2aa-f64c-6e70b9b8063c@amd.com/

arch/x86/include/asm/svm.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index cb1ee53ad3b1..9691081d9231 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -183,6 +183,12 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
#define V_GIF_SHIFT 9
#define V_GIF_MASK (1 << V_GIF_SHIFT)

+#define V_NMI_PENDING_SHIFT 11
+#define V_NMI_PENDING_MASK (1 << V_NMI_PENDING_SHIFT)
+
+#define V_NMI_BLOCKING_SHIFT 12
+#define V_NMI_BLOCKING_MASK (1 << V_NMI_BLOCKING_SHIFT)
+
#define V_INTR_PRIO_SHIFT 16
#define V_INTR_PRIO_MASK (0x0f << V_INTR_PRIO_SHIFT)

@@ -197,6 +203,9 @@ struct __attribute__ ((__packed__)) vmcb_control_area {
#define V_GIF_ENABLE_SHIFT 25
#define V_GIF_ENABLE_MASK (1 << V_GIF_ENABLE_SHIFT)

+#define V_NMI_ENABLE_SHIFT 26
+#define V_NMI_ENABLE_MASK (1 << V_NMI_ENABLE_SHIFT)
+
#define AVIC_ENABLE_SHIFT 31
#define AVIC_ENABLE_MASK (1 << AVIC_ENABLE_SHIFT)

--
2.25.1