[PATCH v3 6/6] x86/vmware: Add TDX hypercall support
From: Alexey Makhalov
Date: Tue Dec 19 2023 - 17:00:51 EST
From: Alexey Makhalov <amakhalov@xxxxxxxxxx>
VMware hypercalls use I/O port, VMCALL or VMMCALL instructions.
Add __tdx_hypercall path to support TDX guests.
No change in high bandwidth hypercalls, as only low bandwidth
ones are supported for TDX guests.
Co-developed-by: Tim Merrifield <timothym@xxxxxxxxxx>
Signed-off-by: Tim Merrifield <timothym@xxxxxxxxxx>
Signed-off-by: Alexey Makhalov <amakhalov@xxxxxxxxxx>
Reviewed-by: Nadav Amit <namit@xxxxxxxxxx>
---
arch/x86/include/asm/vmware.h | 83 +++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/vmware.c | 24 ++++++++++
2 files changed, 107 insertions(+)
diff --git a/arch/x86/include/asm/vmware.h b/arch/x86/include/asm/vmware.h
index 719e41260ece..cad6f5b371a8 100644
--- a/arch/x86/include/asm/vmware.h
+++ b/arch/x86/include/asm/vmware.h
@@ -34,12 +34,65 @@
#define VMWARE_CMD_GETHZ 45
#define VMWARE_CMD_GETVCPU_INFO 68
#define VMWARE_CMD_STEALCLOCK 91
+/*
+ * Hypercall command mask:
+ * bits[6:0] command, range [0, 127]
+ * bits[19:16] sub-command, range [0, 15]
+ */
+#define VMWARE_CMD_MASK 0xf007fU
#define CPUID_VMWARE_FEATURES_ECX_VMMCALL BIT(0)
#define CPUID_VMWARE_FEATURES_ECX_VMCALL BIT(1)
extern u8 vmware_hypercall_mode;
+#define VMWARE_TDX_VENDOR_LEAF 0x1af7e4909ULL
+#define VMWARE_TDX_HCALL_FUNC 1
+
+extern unsigned long vmware_tdx_hypercall(unsigned long cmd,
+ struct tdx_module_args *args);
+
+/*
+ * TDCALL[TDG.VP.VMCALL] uses rax (arg0) and rcx (arg2), while the use of
+ * rbp (arg6) is discouraged by the TDX specification. Therefore, we
+ * remap those registers to r12, r13 and r14, respectively.
+ */
+static inline
+unsigned long vmware_tdx_hypercall_args(unsigned long cmd, unsigned long in1,
+ unsigned long in3, unsigned long in4,
+ unsigned long in5, unsigned long in6,
+ uint32_t *out1, uint32_t *out2,
+ uint32_t *out3, uint32_t *out4,
+ uint32_t *out5, uint32_t *out6)
+{
+ unsigned long ret;
+
+ struct tdx_module_args args = {
+ .rbx = in1,
+ .rdx = in3,
+ .rsi = in4,
+ .rdi = in5,
+ .r14 = in6,
+ };
+
+ ret = vmware_tdx_hypercall(cmd, &args);
+
+ if (out1)
+ *out1 = args.rbx;
+ if (out2)
+ *out2 = args.r13;
+ if (out3)
+ *out3 = args.rdx;
+ if (out4)
+ *out4 = args.rsi;
+ if (out5)
+ *out5 = args.rdi;
+ if (out6)
+ *out6 = args.r14;
+
+ return ret;
+}
+
/*
* The low bandwidth call. The low word of edx is presumed to have OUT bit
* set. The high word of edx may contain input data from the caller.
@@ -67,6 +120,11 @@ unsigned long vmware_hypercall1(unsigned long cmd, unsigned long in1)
{
unsigned long out0;
+ if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
+ return vmware_tdx_hypercall_args(cmd, in1, 0, 0, 0, 0,
+ NULL, NULL, NULL,
+ NULL, NULL, NULL);
+
asm_inline volatile (VMWARE_HYPERCALL
: "=a" (out0)
: [port] "i" (VMWARE_HYPERVISOR_PORT),
@@ -85,6 +143,11 @@ unsigned long vmware_hypercall3(unsigned long cmd, unsigned long in1,
{
unsigned long out0;
+ if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
+ return vmware_tdx_hypercall_args(cmd, in1, 0, 0, 0, 0,
+ out1, out2, NULL,
+ NULL, NULL, NULL);
+
asm_inline volatile (VMWARE_HYPERCALL
: "=a" (out0), "=b" (*out1), "=c" (*out2)
: [port] "i" (VMWARE_HYPERVISOR_PORT),
@@ -104,6 +167,11 @@ unsigned long vmware_hypercall4(unsigned long cmd, unsigned long in1,
{
unsigned long out0;
+ if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
+ return vmware_tdx_hypercall_args(cmd, in1, 0, 0, 0, 0,
+ out1, out2, out3,
+ NULL, NULL, NULL);
+
asm_inline volatile (VMWARE_HYPERCALL
: "=a" (out0), "=b" (*out1), "=c" (*out2), "=d" (*out3)
: [port] "i" (VMWARE_HYPERVISOR_PORT),
@@ -123,6 +191,11 @@ unsigned long vmware_hypercall5(unsigned long cmd, unsigned long in1,
{
unsigned long out0;
+ if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
+ return vmware_tdx_hypercall_args(cmd, in1, in3, in4, in5, 0,
+ NULL, out2, NULL,
+ NULL, NULL, NULL);
+
asm_inline volatile (VMWARE_HYPERCALL
: "=a" (out0), "=c" (*out2)
: [port] "i" (VMWARE_HYPERVISOR_PORT),
@@ -145,6 +218,11 @@ unsigned long vmware_hypercall6(unsigned long cmd, unsigned long in1,
{
unsigned long out0;
+ if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
+ return vmware_tdx_hypercall_args(cmd, in1, in3, 0, 0, 0,
+ NULL, out2, out3,
+ out4, out5, NULL);
+
asm_inline volatile (VMWARE_HYPERCALL
: "=a" (out0), "=c" (*out2), "=d" (*out3), "=S" (*out4),
"=D" (*out5)
@@ -166,6 +244,11 @@ unsigned long vmware_hypercall7(unsigned long cmd, unsigned long in1,
{
unsigned long out0;
+ if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
+ return vmware_tdx_hypercall_args(cmd, in1, in3, in4, in5, 0,
+ out1, out2, out3,
+ NULL, NULL, NULL);
+
asm_inline volatile (VMWARE_HYPERCALL
: "=a" (out0), "=b" (*out1), "=c" (*out2), "=d" (*out3)
: [port] "i" (VMWARE_HYPERVISOR_PORT),
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 3aa1adaed18f..ef07ab7a07e1 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -428,6 +428,30 @@ static bool __init vmware_legacy_x2apic_available(void)
(eax & BIT(VCPU_LEGACY_X2APIC));
}
+#ifdef CONFIG_INTEL_TDX_GUEST
+unsigned long vmware_tdx_hypercall(unsigned long cmd,
+ struct tdx_module_args *args)
+{
+ if (!hypervisor_is_type(X86_HYPER_VMWARE))
+ return 0;
+
+ if (cmd & ~VMWARE_CMD_MASK) {
+ pr_warn("Out of range command %x\n", cmd);
+ return 0;
+ }
+
+ args->r10 = VMWARE_TDX_VENDOR_LEAF;
+ args->r11 = VMWARE_TDX_HCALL_FUNC;
+ args->r12 = VMWARE_HYPERVISOR_MAGIC;
+ args->r13 = cmd;
+
+ __tdx_hypercall(args);
+
+ return args->r12;
+}
+EXPORT_SYMBOL_GPL(vmware_tdx_hypercall);
+#endif
+
#ifdef CONFIG_AMD_MEM_ENCRYPT
static void vmware_sev_es_hcall_prepare(struct ghcb *ghcb,
struct pt_regs *regs)
--
2.39.0