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

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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: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230126221159.8635-5-kirill.shutemov%40linux.intel.com
This commit is contained in:
Kirill A. Shutemov 2023-01-27 01:11:56 +03:00 committed by Dave Hansen
parent c30c4b2555
commit 752d13305c
1 changed files with 30 additions and 5 deletions
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35
arch/x86/coco/tdx/tdcall.S
View file

@ -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