Commit 752d1330 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Dave Hansen
Browse files

x86/tdx: Expand __tdx_hypercall() to handle more arguments 



So far __tdx_hypercall() only handles six arguments for VMCALL.
Expanding it to six more register would allow to cover more use-cases
like ReportFatalError() and Hyper-V hypercalls.

With all preparations in place, the expansion is pretty straight
forward.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230126221159.8635-5-kirill.shutemov%40linux.intel.com
parent c30c4b25

arch/x86/coco/tdx/tdcall.S

+30 −5
Original line number Diff line number Diff line
@@ -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 )



/*

 * __tdx_module_call()  - Used by TDX guests to request services from
@@ -124,6 +130,7 @@ SYM_FUNC_START(__tdx_hypercall) 
	push %r14

	push %r13

	push %r12

	push %rbx

	push %rbp



	/* Free RDI and RSI to be used as TDVMCALL arguments */
@@ -131,12 +138,18 @@ SYM_FUNC_START(__tdx_hypercall) 
	movq %rsi, %rbp



	/* 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
@@ -178,12 +191,18 @@ SYM_FUNC_START(__tdx_hypercall) 
	testq $TDX_HCALL_HAS_OUTPUT, %rbp

	jz .Lout



	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
@@ -191,14 +210,20 @@ SYM_FUNC_START(__tdx_hypercall) 
	/*

	 * 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 %rsi,  %rsi

	xor %rdx,  %rdx



	/* Restore callee-saved GPRs as mandated by the x86_64 ABI */

	pop %rbp

	pop %rbx

	pop %r12

	pop %r13

	pop %r14