[PATCH v12 050/106] KVM: TDX: MTRR: implement get_mt_mask() for TDX
From: isaku . yamahata
Date: Mon Feb 27 2023 - 03:27:22 EST
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Because TDX virtualize cpuid[0x1].EDX[MTRR: bit 12] to fixed 1, guest TD
thinks MTRR is supported. Although TDX supports only WB for private GPA,
it's desirable to support MTRR for shared GPA. As guest access to MTRR
MSRs causes #VE and KVM/x86 tracks the values of MTRR MSRs, the remining
part is to implement get_mt_mask method for TDX for shared GPA.
Pass around shared bit from kvm fault handler to get_mt_mask method so that
it can determine if the gfn is shared or private. Implement get_mt_mask()
following vmx case for shared GPA and return WB for private GPA.
the existing vmx_get_mt_mask() can't be directly used as CPU state(CR0.CD)
is protected. GFN passed to kvm_mtrr_check_gfn_range_consistency() should
include shared bit.
Suggested-by: Kai Huang <kai.huang@xxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
Changes from v11 to V12
- Make common function for VMX and TDX
- pass around shared bit from KVM fault handler to get_mt_mask method
- updated commit message
---
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/mmu/spte.c | 5 +++--
arch/x86/kvm/mmu/spte.h | 2 +-
arch/x86/kvm/vmx/common.h | 2 ++
arch/x86/kvm/vmx/main.c | 11 ++++++++++-
arch/x86/kvm/vmx/tdx.c | 17 +++++++++++++++++
arch/x86/kvm/vmx/vmx.c | 5 +++--
arch/x86/kvm/vmx/x86_ops.h | 2 ++
8 files changed, 39 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6421f92e618e..0c852517c0e7 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4555,7 +4555,7 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
if (shadow_memtype_mask && kvm_arch_has_noncoherent_dma(vcpu->kvm)) {
for ( ; fault->max_level > PG_LEVEL_4K; --fault->max_level) {
int page_num = KVM_PAGES_PER_HPAGE(fault->max_level);
- gfn_t base = fault->gfn & ~(page_num - 1);
+ gfn_t base = (fault->addr >> PAGE_SHIFT) & ~(page_num - 1);
if (kvm_mtrr_check_gfn_range_consistency(vcpu, base, page_num))
break;
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index 48e17588a127..9c874bca69f6 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -137,13 +137,14 @@ bool spte_has_volatile_bits(u64 spte)
bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
const struct kvm_memory_slot *slot,
- unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn,
+ unsigned int pte_access, gfn_t gfn_including_shared, kvm_pfn_t pfn,
u64 old_spte, bool prefetch, bool can_unsync,
bool host_writable, u64 *new_spte)
{
int level = sp->role.level;
u64 spte = SPTE_MMU_PRESENT_MASK;
bool wrprot = false;
+ gfn_t gfn = gfn_including_shared & ~kvm_gfn_shared_mask(vcpu->kvm);
WARN_ON_ONCE(!pte_access && !shadow_present_mask);
@@ -191,7 +192,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
spte |= PT_PAGE_SIZE_MASK;
if (shadow_memtype_mask)
- spte |= static_call(kvm_x86_get_mt_mask)(vcpu, gfn,
+ spte |= static_call(kvm_x86_get_mt_mask)(vcpu, gfn_including_shared,
kvm_is_mmio_pfn(pfn));
if (host_writable)
spte |= shadow_host_writable_mask;
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 7046671b08cb..067ea1ae3a13 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -481,7 +481,7 @@ bool spte_has_volatile_bits(u64 spte);
bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
const struct kvm_memory_slot *slot,
- unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn,
+ unsigned int pte_access, gfn_t gfn_including_shared, kvm_pfn_t pfn,
u64 old_spte, bool prefetch, bool can_unsync,
bool host_writable, u64 *new_spte);
u64 make_huge_page_split_spte(struct kvm *kvm, u64 huge_spte,
diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index 235908f3e044..422b24af7fc1 100644
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -6,6 +6,8 @@
#include "mmu.h"
+u8 __vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio, bool check_cr0_cd);
+
static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_t gpa,
unsigned long exit_qualification)
{
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index a2ca09f10b6e..f42617c7aeaf 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -3,6 +3,7 @@
#include "x86_ops.h"
#include "mmu.h"
+#include "common.h"
#include "vmx.h"
#include "nested.h"
#include "mmu.h"
@@ -206,6 +207,14 @@ static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
vmx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
}
+static u8 vt_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
+{
+ if (is_td_vcpu(vcpu))
+ return tdx_get_mt_mask(vcpu, gfn, is_mmio);
+
+ return __vmx_get_mt_mask(vcpu, gfn, is_mmio, true);
+}
+
static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
{
if (!is_td(kvm))
@@ -326,7 +335,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.set_tss_addr = vmx_set_tss_addr,
.set_identity_map_addr = vmx_set_identity_map_addr,
- .get_mt_mask = vmx_get_mt_mask,
+ .get_mt_mask = vt_get_mt_mask,
.get_exit_info = vmx_get_exit_info,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 8f191177bfe9..f532f5c352f3 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -5,6 +5,7 @@
#include "capabilities.h"
#include "x86_ops.h"
+#include "common.h"
#include "tdx.h"
#include "vmx.h"
#include "x86.h"
@@ -345,6 +346,22 @@ int tdx_vm_init(struct kvm *kvm)
return 0;
}
+u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
+{
+ /* TDX private GPA is always WB. */
+ if (kvm_gfn_private(vcpu->kvm, gfn)) {
+ /* MMIO is only for shared GPA. */
+ WARN_ON_ONCE(is_mmio);
+ return MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT;
+ }
+
+ /* Drop shared bit as MTRR doesn't know about shared bit. */
+ gfn = kvm_gfn_private(vcpu->kvm, gfn);
+
+ /* As TDX enforces CR0.CD to 0, pass check_cr0_cd = false. */
+ return __vmx_get_mt_mask(vcpu, gfn, is_mmio, false);
+}
+
int tdx_vcpu_create(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *e;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 3ff3b33fe9af..72da86abf989 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7552,7 +7552,8 @@ int vmx_vm_init(struct kvm *kvm)
return 0;
}
-u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
+u8 __vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio,
+ bool check_cr0_cd)
{
u8 cache;
@@ -7580,7 +7581,7 @@ u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
if (!kvm_arch_has_noncoherent_dma(vcpu->kvm))
return (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT) | VMX_EPT_IPAT_BIT;
- if (kvm_read_cr0(vcpu) & X86_CR0_CD) {
+ if (check_cr0_cd && kvm_read_cr0(vcpu) & X86_CR0_CD) {
if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))
cache = MTRR_TYPE_WRBACK;
else
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 2d1d53d14843..69f66e857ce5 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -154,6 +154,7 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
int tdx_vcpu_create(struct kvm_vcpu *vcpu);
void tdx_vcpu_free(struct kvm_vcpu *vcpu);
void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
+u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
@@ -178,6 +179,7 @@ static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOP
static inline int tdx_vcpu_create(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
static inline void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) {}
+static inline u8 tdx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) { return 0; }
static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
--
2.25.1