diff options
Diffstat (limited to 'arch/x86/coco/tdx/tdcall.S')
| -rw-r--r-- | arch/x86/coco/tdx/tdcall.S | 81 |
1 files changed, 58 insertions, 23 deletions
diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index ad0d51f03cb4..6a255e6809bc 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -13,6 +13,12 @@ /* * Bitmasks of exposed registers (with VMM). */ +#define TDX_RDX BIT(2) +#define TDX_RBX BIT(3) +#define TDX_RSI BIT(6) +#define TDX_RDI BIT(7) +#define TDX_R8 BIT(8) +#define TDX_R9 BIT(9) #define TDX_R10 BIT(10) #define TDX_R11 BIT(11) #define TDX_R12 BIT(12) @@ -27,9 +33,9 @@ * details can be found in TDX GHCI specification, section * titled "TDCALL [TDG.VP.VMCALL] leaf". */ -#define TDVMCALL_EXPOSE_REGS_MASK ( TDX_R10 | TDX_R11 | \ - TDX_R12 | TDX_R13 | \ - TDX_R14 | TDX_R15 ) +#define TDVMCALL_EXPOSE_REGS_MASK \ + ( TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8 | TDX_R9 | \ + TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15 ) .section .noinstr.text, "ax" @@ -126,25 +132,38 @@ SYM_FUNC_START(__tdx_hypercall) push %r14 push %r13 push %r12 + push %rbx + + /* Free RDI and RSI to be used as TDVMCALL arguments */ + movq %rdi, %rax + push %rsi + + /* Copy hypercall registers from arg struct: */ + movq TDX_HYPERCALL_r8(%rax), %r8 + movq TDX_HYPERCALL_r9(%rax), %r9 + movq TDX_HYPERCALL_r10(%rax), %r10 + movq TDX_HYPERCALL_r11(%rax), %r11 + movq TDX_HYPERCALL_r12(%rax), %r12 + movq TDX_HYPERCALL_r13(%rax), %r13 + movq TDX_HYPERCALL_r14(%rax), %r14 + movq TDX_HYPERCALL_r15(%rax), %r15 + movq TDX_HYPERCALL_rdi(%rax), %rdi + movq TDX_HYPERCALL_rsi(%rax), %rsi + movq TDX_HYPERCALL_rbx(%rax), %rbx + movq TDX_HYPERCALL_rdx(%rax), %rdx + + push %rax /* Mangle function call ABI into TDCALL ABI: */ /* Set TDCALL leaf ID (TDVMCALL (0)) in RAX */ xor %eax, %eax - /* Copy hypercall registers from arg struct: */ - movq TDX_HYPERCALL_r10(%rdi), %r10 - movq TDX_HYPERCALL_r11(%rdi), %r11 - movq TDX_HYPERCALL_r12(%rdi), %r12 - movq TDX_HYPERCALL_r13(%rdi), %r13 - movq TDX_HYPERCALL_r14(%rdi), %r14 - movq TDX_HYPERCALL_r15(%rdi), %r15 - movl $TDVMCALL_EXPOSE_REGS_MASK, %ecx tdcall /* - * RAX==0 indicates a failure of the TDVMCALL mechanism itself and that + * RAX!=0 indicates a failure of the TDVMCALL mechanism itself and that * something has gone horribly wrong with the TDX module. * * The return status of the hypercall operation is in a separate @@ -154,30 +173,46 @@ SYM_FUNC_START(__tdx_hypercall) testq %rax, %rax jne .Lpanic - /* TDVMCALL leaf return code is in R10 */ - movq %r10, %rax + pop %rax /* Copy hypercall result registers to arg struct if needed */ - testq $TDX_HCALL_HAS_OUTPUT, %rsi + testq $TDX_HCALL_HAS_OUTPUT, (%rsp) jz .Lout - movq %r10, TDX_HYPERCALL_r10(%rdi) - movq %r11, TDX_HYPERCALL_r11(%rdi) - movq %r12, TDX_HYPERCALL_r12(%rdi) - movq %r13, TDX_HYPERCALL_r13(%rdi) - movq %r14, TDX_HYPERCALL_r14(%rdi) - movq %r15, TDX_HYPERCALL_r15(%rdi) + movq %r8, TDX_HYPERCALL_r8(%rax) + movq %r9, TDX_HYPERCALL_r9(%rax) + movq %r10, TDX_HYPERCALL_r10(%rax) + movq %r11, TDX_HYPERCALL_r11(%rax) + movq %r12, TDX_HYPERCALL_r12(%rax) + movq %r13, TDX_HYPERCALL_r13(%rax) + movq %r14, TDX_HYPERCALL_r14(%rax) + movq %r15, TDX_HYPERCALL_r15(%rax) + movq %rdi, TDX_HYPERCALL_rdi(%rax) + movq %rsi, TDX_HYPERCALL_rsi(%rax) + movq %rbx, TDX_HYPERCALL_rbx(%rax) + movq %rdx, TDX_HYPERCALL_rdx(%rax) .Lout: + /* TDVMCALL leaf return code is in R10 */ + movq %r10, %rax + /* * Zero out registers exposed to the VMM to avoid speculative execution * with VMM-controlled values. This needs to include all registers - * present in TDVMCALL_EXPOSE_REGS_MASK (except R12-R15). R12-R15 - * context will be restored. + * present in TDVMCALL_EXPOSE_REGS_MASK, except RBX, and R12-R15 which + * will be restored. */ + xor %r8d, %r8d + xor %r9d, %r9d xor %r10d, %r10d xor %r11d, %r11d + xor %rdi, %rdi + xor %rdx, %rdx + + /* Remove TDX_HCALL_* flags from the stack */ + pop %rsi /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ + pop %rbx pop %r12 pop %r13 pop %r14 |