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Message-ID: <20250226195529.2314580-13-pbonzini@redhat.com>
Date: Wed, 26 Feb 2025 14:55:12 -0500
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
kvm@...r.kernel.org
Cc: seanjc@...gle.com,
Yan Zhao <yan.y.zhao@...el.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
Sean Christopherson <sean.j.christopherson@...el.com>,
Isaku Yamahata <isaku.yamahata@...el.com>
Subject: [PATCH 12/29] KVM: TDX: Add load_mmu_pgd method for TDX
From: Sean Christopherson <sean.j.christopherson@...el.com>
TDX uses two EPT pointers, one for the private half of the GPA space and
one for the shared half. The private half uses the normal EPT_POINTER vmcs
field, which is managed in a special way by the TDX module. For TDX, KVM is
not allowed to operate on it directly. The shared half uses a new
SHARED_EPT_POINTER field and will be managed by the conventional MMU
management operations that operate directly on the EPT root. This means for
TDX the .load_mmu_pgd() operation will need to know to use the
SHARED_EPT_POINTER field instead of the normal one. Add a new wrapper in
x86 ops for load_mmu_pgd() that either directs the write to the existing
vmx implementation or a TDX one.
tdx_load_mmu_pgd() is so much simpler than vmx_load_mmu_pgd() since for the
TDX mode of operation, EPT will always be used and KVM does not need to be
involved in virtualization of CR3 behavior. So tdx_load_mmu_pgd() can
simply write to SHARED_EPT_POINTER.
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Co-developed-by: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@...el.com>
Co-developed-by: Yan Zhao <yan.y.zhao@...el.com>
Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>
Message-ID: <20241112073601.22084-1-yan.y.zhao@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
arch/x86/include/asm/vmx.h | 1 +
arch/x86/kvm/vmx/main.c | 13 ++++++++++++-
arch/x86/kvm/vmx/tdx.c | 15 +++++++++++++++
arch/x86/kvm/vmx/x86_ops.h | 4 ++++
4 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index f7fd4369b821..9298fb9d4bb3 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -256,6 +256,7 @@ enum vmcs_field {
TSC_MULTIPLIER_HIGH = 0x00002033,
TERTIARY_VM_EXEC_CONTROL = 0x00002034,
TERTIARY_VM_EXEC_CONTROL_HIGH = 0x00002035,
+ SHARED_EPT_POINTER = 0x0000203C,
PID_POINTER_TABLE = 0x00002042,
PID_POINTER_TABLE_HIGH = 0x00002043,
GUEST_PHYSICAL_ADDRESS = 0x00002400,
diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index e7d402b3a90d..8ed08c53c02f 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -98,6 +98,17 @@ static void vt_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
vmx_vcpu_reset(vcpu, init_event);
}
+static void vt_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
+ int pgd_level)
+{
+ if (is_td_vcpu(vcpu)) {
+ tdx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
+ return;
+ }
+
+ vmx_load_mmu_pgd(vcpu, root_hpa, pgd_level);
+}
+
static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
{
if (!is_td(kvm))
@@ -231,7 +242,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.write_tsc_offset = vmx_write_tsc_offset,
.write_tsc_multiplier = vmx_write_tsc_multiplier,
- .load_mmu_pgd = vmx_load_mmu_pgd,
+ .load_mmu_pgd = vt_load_mmu_pgd,
.check_intercept = vmx_check_intercept,
.handle_exit_irqoff = vmx_handle_exit_irqoff,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 3fb5410cecb1..ec86c97ada80 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -32,6 +32,9 @@
bool enable_tdx __ro_after_init;
module_param_named(tdx, enable_tdx, bool, 0444);
+#define TDX_SHARED_BIT_PWL_5 gpa_to_gfn(BIT_ULL(51))
+#define TDX_SHARED_BIT_PWL_4 gpa_to_gfn(BIT_ULL(47))
+
static enum cpuhp_state tdx_cpuhp_state;
static const struct tdx_sys_info *tdx_sysinfo;
@@ -490,6 +493,18 @@ void tdx_vcpu_free(struct kvm_vcpu *vcpu)
tdx->state = VCPU_TD_STATE_UNINITIALIZED;
}
+
+void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int pgd_level)
+{
+ u64 shared_bit = (pgd_level == 5) ? TDX_SHARED_BIT_PWL_5 :
+ TDX_SHARED_BIT_PWL_4;
+
+ if (KVM_BUG_ON(shared_bit != kvm_gfn_direct_bits(vcpu->kvm), vcpu->kvm))
+ return;
+
+ td_vmcs_write64(to_tdx(vcpu), SHARED_EPT_POINTER, root_hpa);
+}
+
static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
{
const struct tdx_sys_info_td_conf *td_conf = &tdx_sysinfo->td_conf;
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index b6365939cf9f..ad1c2f3e546e 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -131,6 +131,8 @@ int tdx_vcpu_create(struct kvm_vcpu *vcpu);
void tdx_vcpu_free(struct kvm_vcpu *vcpu);
int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
+
+void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);
#else
static inline int tdx_vm_init(struct kvm *kvm) { return -EOPNOTSUPP; }
static inline void tdx_mmu_release_hkid(struct kvm *kvm) {}
@@ -141,6 +143,8 @@ static inline int tdx_vcpu_create(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }
+
+static inline void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level) {}
#endif
#endif /* __KVM_X86_VMX_X86_OPS_H */
--
2.43.5
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