[PATCH v2 06/24] KVM: TDX: Add accessors VMX VMCS helpers

Yan Zhao
2024-11-12T07:38:21Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

TDX defines SEAMCALL APIs to access TDX control structures corresponding to
the VMX VMCS. Introduce helper accessors to hide its SEAMCALL ABI details.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
TDX MMU part 2 v2:
-Move inline warning msgs to tdh_vp_rd/wr_failed() (Paolo)

TDX MMU part 2 v1:
- Update for the wrapper functions for SEAMCALLs. (Sean)
- Eliminate kvm_mmu_free_private_spt() and open code it.
- Fix bisectability issues in headers (Kai)
- Updates from seamcall overhaul (Kai)

v19:
- deleted unnecessary stub functions,
tdvps_state_non_arch_check() and tdvps_management_check().
---
arch/x86/kvm/vmx/tdx.c | 13 +++++++
arch/x86/kvm/vmx/tdx.h | 88 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 101 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 7fb32d3b1aae..ed4473d0c2cd 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -32,6 +32,19 @@ static enum cpuhp_state tdx_cpuhp_state;

static const struct tdx_sys_info *tdx_sysinfo;

+void tdh_vp_rd_failed(struct vcpu_tdx *tdx, char *uclass, u32 field, u64 err)
+{
+ KVM_BUG_ON(1, tdx->vcpu.kvm);
+ pr_err("TDH_VP_RD[%s.0x%x] failed 0x%llx\n", uclass, field, err);
+}
+
+void tdh_vp_wr_failed(struct vcpu_tdx *tdx, char *uclass, char *op, u32 field,
+ u64 val, u64 err)
+{
+ KVM_BUG_ON(1, tdx->vcpu.kvm);
+ pr_err("TDH_VP_WR[%s.0x%x]%s0x%llx failed: 0x%llx\n", uclass, field, op, val, err);
+}
+
#define KVM_SUPPORTED_TD_ATTRS (TDX_TD_ATTR_SEPT_VE_DISABLE)

static u64 tdx_get_supported_attrs(const struct tdx_sys_info_td_conf *td_conf)
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
index 1b78a7ea988e..727bcf25d731 100644
--- a/arch/x86/kvm/vmx/tdx.h
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -49,6 +49,10 @@ struct vcpu_tdx {
enum vcpu_tdx_state state;
};

+void tdh_vp_rd_failed(struct vcpu_tdx *tdx, char *uclass, u32 field, u64 err);
+void tdh_vp_wr_failed(struct vcpu_tdx *tdx, char *uclass, char *op, u32 field,
+ u64 val, u64 err);
+
static inline bool is_td(struct kvm *kvm)
{
return kvm->arch.vm_type == KVM_X86_TDX_VM;
@@ -80,6 +84,90 @@ static __always_inline u64 td_tdcs_exec_read64(struct kvm_tdx *kvm_tdx, u32 fiel
}
return data;
}
+
+static __always_inline void tdvps_vmcs_check(u32 field, u8 bits)
+{
+#define VMCS_ENC_ACCESS_TYPE_MASK 0x1UL
+#define VMCS_ENC_ACCESS_TYPE_FULL 0x0UL
+#define VMCS_ENC_ACCESS_TYPE_HIGH 0x1UL
+#define VMCS_ENC_ACCESS_TYPE(field) ((field) & VMCS_ENC_ACCESS_TYPE_MASK)
+
+ /* TDX is 64bit only. HIGH field isn't supported. */
+ BUILD_BUG_ON_MSG(__builtin_constant_p(field) &&
+ VMCS_ENC_ACCESS_TYPE(field) == VMCS_ENC_ACCESS_TYPE_HIGH,
+ "Read/Write to TD VMCS *_HIGH fields not supported");
+
+ BUILD_BUG_ON(bits != 16 && bits != 32 && bits != 64);
+
+#define VMCS_ENC_WIDTH_MASK GENMASK(14, 13)
+#define VMCS_ENC_WIDTH_16BIT (0UL << 13)
+#define VMCS_ENC_WIDTH_64BIT (1UL << 13)
+#define VMCS_ENC_WIDTH_32BIT (2UL << 13)
+#define VMCS_ENC_WIDTH_NATURAL (3UL << 13)
+#define VMCS_ENC_WIDTH(field) ((field) & VMCS_ENC_WIDTH_MASK)
+
+ /* TDX is 64bit only. i.e. natural width = 64bit. */
+ BUILD_BUG_ON_MSG(bits != 64 && __builtin_constant_p(field) &&
+ (VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_64BIT ||
+ VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_NATURAL),
+ "Invalid TD VMCS access for 64-bit field");
+ BUILD_BUG_ON_MSG(bits != 32 && __builtin_constant_p(field) &&
+ VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_32BIT,
+ "Invalid TD VMCS access for 32-bit field");
+ BUILD_BUG_ON_MSG(bits != 16 && __builtin_constant_p(field) &&
+ VMCS_ENC_WIDTH(field) == VMCS_ENC_WIDTH_16BIT,
+ "Invalid TD VMCS access for 16-bit field");
+}
+
+#define TDX_BUILD_TDVPS_ACCESSORS(bits, uclass, lclass) \
+static __always_inline u##bits td_##lclass##_read##bits(struct vcpu_tdx *tdx, \
+ u32 field) \
+{ \
+ u64 err, data; \
+ \
+ tdvps_##lclass##_check(field, bits); \
+ err = tdh_vp_rd(tdx->tdvpr_pa, TDVPS_##uclass(field), &data); \
+ if (unlikely(err)) { \
+ tdh_vp_rd_failed(tdx, #uclass, field, err); \
+ return 0; \
+ } \
+ return (u##bits)data; \
+} \
+static __always_inline void td_##lclass##_write##bits(struct vcpu_tdx *tdx, \
+ u32 field, u##bits val) \
+{ \
+ u64 err; \
+ \
+ tdvps_##lclass##_check(field, bits); \
+ err = tdh_vp_wr(tdx->tdvpr_pa, TDVPS_##uclass(field), val, \
+ GENMASK_ULL(bits - 1, 0)); \
+ if (unlikely(err)) \
+ tdh_vp_wr_failed(tdx, #uclass, " = ", field, (u64)val, err); \
+} \
+static __always_inline void td_##lclass##_setbit##bits(struct vcpu_tdx *tdx, \
+ u32 field, u64 bit) \
+{ \
+ u64 err; \
+ \
+ tdvps_##lclass##_check(field, bits); \
+ err = tdh_vp_wr(tdx->tdvpr_pa, TDVPS_##uclass(field), bit, bit); \
+ if (unlikely(err)) \
+ tdh_vp_wr_failed(tdx, #uclass, " |= ", field, bit, err); \
+} \
+static __always_inline void td_##lclass##_clearbit##bits(struct vcpu_tdx *tdx, \
+ u32 field, u64 bit) \
+{ \
+ u64 err; \
+ \
+ tdvps_##lclass##_check(field, bits); \
+ err = tdh_vp_wr(tdx->tdvpr_pa, TDVPS_##uclass(field), 0, bit); \
+ if (unlikely(err)) \
+ tdh_vp_wr_failed(tdx, #uclass, " &= ~", field, bit, err);\
+}
+
+TDX_BUILD_TDVPS_ACCESSORS(16, VMCS, vmcs);
+TDX_BUILD_TDVPS_ACCESSORS(32, VMCS, vmcs);
+TDX_BUILD_TDVPS_ACCESSORS(64, VMCS, vmcs);
#else
static inline void tdx_bringup(void) {}
static inline void tdx_cleanup(void) {}
--
2.43.2