[PATCH v2 4/7] KVM: SVM: hyper-v: Nested enlightenments in VMCB

Vineeth Pillai
2021-04-15T13:44:19Z

Add Hyper-V specific fields in VMCB to support SVM enlightenments.
Also a small refactoring of VMCB clean bits handling.

Signed-off-by: Vineeth Pillai <viremana@linux.microsoft.com>
---
arch/x86/include/asm/svm.h | 24 +++++++++++++++++++++++-
arch/x86/kvm/svm/svm.c | 8 ++++++++
arch/x86/kvm/svm/svm.h | 30 ++++++++++++++++++++++++++++--
3 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 1c561945b426..3586d7523ce8 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -322,9 +322,31 @@ static inline void __unused_size_checks(void)
BUILD_BUG_ON(sizeof(struct ghcb) != EXPECTED_GHCB_SIZE);
}

+
+#if IS_ENABLED(CONFIG_HYPERV)
+struct __packed hv_enlightenments {
+ struct __packed hv_enlightenments_control {
+ u32 nested_flush_hypercall:1;
+ u32 msr_bitmap:1;
+ u32 enlightened_npt_tlb: 1;
+ u32 reserved:29;
+ } hv_enlightenments_control;
+ u32 hv_vp_id;
+ u64 hv_vm_id;
+ u64 partition_assist_page;
+ u64 reserved;
+};
+#define VMCB_CONTROL_END 992 // 32 bytes for Hyper-V
+#else
+#define VMCB_CONTROL_END 1024
+#endif
+
struct vmcb {
struct vmcb_control_area control;
- u8 reserved_control[1024 - sizeof(struct vmcb_control_area)];
+ u8 reserved_control[VMCB_CONTROL_END - sizeof(struct vmcb_control_area)];
+#if IS_ENABLED(CONFIG_HYPERV)
+ struct hv_enlightenments hv_enlightenments;
+#endif
struct vmcb_save_area save;
} __packed;

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index baee91c1e936..2ad1f55c88d0 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -31,6 +31,7 @@
#include <asm/tlbflush.h>
#include <asm/desc.h>
#include <asm/debugreg.h>
+#include <asm/hypervisor.h>
#include <asm/kvm_para.h>
#include <asm/irq_remapping.h>
#include <asm/spec-ctrl.h>
@@ -122,6 +123,8 @@ bool npt_enabled = true;
bool npt_enabled;
#endif

+u32 __read_mostly vmcb_all_clean_mask = VMCB_ALL_CLEAN_MASK;
+
/*
* These 2 parameters are used to config the controls for Pause-Loop Exiting:
* pause_filter_count: On processors that support Pause filtering(indicated
@@ -1051,6 +1054,11 @@ static __init int svm_hardware_setup(void)
*/
allow_smaller_maxphyaddr = !npt_enabled;

+#if IS_ENABLED(CONFIG_HYPERV)
+ if (hypervisor_is_type(X86_HYPER_MS_HYPERV))
+ vmcb_all_clean_mask |= VMCB_HYPERV_CLEAN_MASK;
+#endif
+
return 0;

err:
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 39e071fdab0c..63ed05c8027b 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -33,6 +33,11 @@ static const u32 host_save_user_msrs[] = {
extern u32 msrpm_offsets[MSRPM_OFFSETS] __read_mostly;
extern bool npt_enabled;

+/*
+ * Clean bits in VMCB.
+ * VMCB_ALL_CLEAN_MASK and VMCB_HYPERV_CLEAN_MASK might
+ * also need to be updated if this enum is modified.
+ */
enum {
VMCB_INTERCEPTS, /* Intercept vectors, TSC offset,
pause filter count */
@@ -50,12 +55,28 @@ enum {
* AVIC PHYSICAL_TABLE pointer,
* AVIC LOGICAL_TABLE pointer
*/
- VMCB_DIRTY_MAX,
+#if IS_ENABLED(CONFIG_HYPERV)
+ VMCB_HV_NESTED_ENLIGHTENMENTS = 31,
+#endif
};

+#define VMCB_ALL_CLEAN_MASK ( \
+ (1U << VMCB_INTERCEPTS) | (1U << VMCB_PERM_MAP) | \
+ (1U << VMCB_ASID) | (1U << VMCB_INTR) | \
+ (1U << VMCB_NPT) | (1U << VMCB_CR) | (1U << VMCB_DR) | \
+ (1U << VMCB_DT) | (1U << VMCB_SEG) | (1U << VMCB_CR2) | \
+ (1U << VMCB_LBR) | (1U << VMCB_AVIC) \
+ )
+
+#if IS_ENABLED(CONFIG_HYPERV)
+#define VMCB_HYPERV_CLEAN_MASK (1U << VMCB_HV_NESTED_ENLIGHTENMENTS)
+#endif
+
/* TPR and CR2 are always written before VMRUN */
#define VMCB_ALWAYS_DIRTY_MASK ((1U << VMCB_INTR) | (1U << VMCB_CR2))

+extern u32 vmcb_all_clean_mask __read_mostly;
+
struct kvm_sev_info {
bool active; /* SEV enabled guest */
bool es_active; /* SEV-ES enabled guest */
@@ -230,7 +251,7 @@ static inline void vmcb_mark_all_dirty(struct vmcb *vmcb)

static inline void vmcb_mark_all_clean(struct vmcb *vmcb)
{
- vmcb->control.clean = ((1 << VMCB_DIRTY_MAX) - 1)
+ vmcb->control.clean = vmcb_all_clean_mask
& ~VMCB_ALWAYS_DIRTY_MASK;
}

@@ -239,6 +260,11 @@ static inline void vmcb_mark_dirty(struct vmcb *vmcb, int bit)
vmcb->control.clean &= ~(1 << bit);
}

+static inline bool vmcb_is_clean(struct vmcb *vmcb, int bit)
+{
+ return (vmcb->control.clean & (1 << bit));
+}
+
static inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
{
return container_of(vcpu, struct vcpu_svm, vcpu);
--
2.25.1