On Tue, Aug 30, 2022 at 10:19:46PM +0000, Sagi Shahar sagis@google.com wrote:
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx.h b/tools/testing/selftests/kvm/lib/x86_64/tdx.h index 61b997dfc420..d5de52657112 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/tdx.h +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx.h @@ -51,6 +51,12 @@ #define _PAGE_RW (1UL<<1) /* writeable */ #define _PAGE_PS (1UL<<7) /* page size bit*/ +#define TDX_INSTRUCTION_IO 30
+#define TDX_SUCCESS_PORT 0x30 +#define TDX_IO_READ 0 +#define TDX_IO_WRITE 1
#define GDT_ENTRY(flags, base, limit) \ ((((base) & 0xff000000ULL) << (56-24)) | \ (((flags) & 0x0000f0ffULL) << 40) | \ @@ -83,4 +89,147 @@ void prepare_source_image(struct kvm_vm *vm, void *guest_code, size_t guest_code_size, uint64_t guest_code_signature); +/*
- Generic TDCALL function that can be used to communicate with TDX module or
- VMM.
- Input operands: rax, rbx, rcx, rdx, r8-r15, rbp, rsi, rdi
- Output operands: rax, r8-r15, rbx, rdx, rdi, rsi
- rcx is actually a bitmap to tell TDX module which register values will be
- exposed to the VMM.
- XMM0-XMM15 registers can be used as input operands but the current
- implementation does not support it yet.
- */
+static inline void tdcall(struct kvm_regs *regs) +{
- asm volatile (
"mov %13, %%rax;\n\t""mov %14, %%rbx;\n\t""mov %15, %%rcx;\n\t""mov %16, %%rdx;\n\t""mov %17, %%r8;\n\t""mov %18, %%r9;\n\t""mov %19, %%r10;\n\t""mov %20, %%r11;\n\t""mov %21, %%r12;\n\t""mov %22, %%r13;\n\t""mov %23, %%r14;\n\t""mov %24, %%r15;\n\t""mov %25, %%rbp;\n\t""mov %26, %%rsi;\n\t""mov %27, %%rdi;\n\t"".byte 0x66, 0x0F, 0x01, 0xCC;\n\t""mov %%rax, %0;\n\t""mov %%rbx, %1;\n\t""mov %%rdx, %2;\n\t""mov %%r8, %3;\n\t""mov %%r9, %4;\n\t""mov %%r10, %5;\n\t""mov %%r11, %6;\n\t""mov %%r12, %7;\n\t""mov %%r13, %8;\n\t""mov %%r14, %9;\n\t""mov %%r15, %10;\n\t""mov %%rsi, %11;\n\t""mov %%rdi, %12;\n\t": "=m" (regs->rax), "=m" (regs->rbx), "=m" (regs->rdx),"=m" (regs->r8), "=m" (regs->r9), "=m" (regs->r10),"=m" (regs->r11), "=m" (regs->r12), "=m" (regs->r13),"=m" (regs->r14), "=m" (regs->r15), "=m" (regs->rsi),"=m" (regs->rdi): "m" (regs->rax), "m" (regs->rbx), "m" (regs->rcx),"m" (regs->rdx), "m" (regs->r8), "m" (regs->r9),"m" (regs->r10), "m" (regs->r11), "m" (regs->r12),"m" (regs->r13), "m" (regs->r14), "m" (regs->r15),"m" (regs->rbp), "m" (regs->rsi), "m" (regs->rdi): "rax", "rbx", "rcx", "rdx", "r8", "r9", "r10", "r11","r12", "r13", "r14", "r15", "rbp", "rsi", "rdi");+}
Sometimes compiler (my gcc is (Ubuntu 11.1.0-1ubuntu1~20.04) 11.1.0) doesn't like clobering the frame pointer as follows. (I edited the caller site for other test.)
x86_64/tdx_vm_tests.c:343:1: error: bp cannot be used in ‘asm’ here
I ended up the following workaround. I didn't use pushq/popq pair because I didn't want to play with offset in the stack of the caller.
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx.h b/tools/testing/selftests/kvm/lib/x86_64/tdx.h index aa6961c6f304..8ddf3b64f003 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/tdx.h +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx.h @@ -122,7 +122,11 @@ void prepare_source_image(struct kvm_vm *vm, void *guest_code, */ static inline void tdcall(struct kvm_regs *regs) { + unsigned long saved_rbp = 0; + asm volatile ( + /* gcc complains that frame pointer %rbp can't be clobbered. */ + "movq %%rbp, %28;\n\t" "mov %13, %%rax;\n\t" "mov %14, %%rbx;\n\t" "mov %15, %%rcx;\n\t" @@ -152,6 +156,8 @@ static inline void tdcall(struct kvm_regs *regs) "mov %%r15, %10;\n\t" "mov %%rsi, %11;\n\t" "mov %%rdi, %12;\n\t" + "movq %28, %%rbp\n\t" + "movq $0, %28\n\t" : "=m" (regs->rax), "=m" (regs->rbx), "=m" (regs->rdx), "=m" (regs->r8), "=m" (regs->r9), "=m" (regs->r10), "=m" (regs->r11), "=m" (regs->r12), "=m" (regs->r13), @@ -161,9 +167,10 @@ static inline void tdcall(struct kvm_regs *regs) "m" (regs->rdx), "m" (regs->r8), "m" (regs->r9), "m" (regs->r10), "m" (regs->r11), "m" (regs->r12), "m" (regs->r13), "m" (regs->r14), "m" (regs->r15), - "m" (regs->rbp), "m" (regs->rsi), "m" (regs->rdi) + "m" (regs->rbp), "m" (regs->rsi), "m" (regs->rdi), + "m" (saved_rbp) : "rax", "rbx", "rcx", "rdx", "r8", "r9", "r10", "r11", - "r12", "r13", "r14", "r15", "rbp", "rsi", "rdi"); + "r12", "r13", "r14", "r15", "rsi", "rdi"); }