Commit 7b664cc3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86_tdx_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 tdx update from Dave Hansen:
 "The original tdx hypercall assembly code took two flags in %RSI to
  tweak its behavior at runtime. PeterZ recently axed one flag in commit
  e80a48ba ("x86/tdx: Remove TDX_HCALL_ISSUE_STI").

  Kill the other flag too and tweak the 'output' mode with an assembly
  macro instead. This results in elimination of one push/pop pair and
  overall easier to read assembly.

   - Do conditional __tdx_hypercall() 'output' processing via an
     assembly macro argument rather than a runtime register"

* tag 'x86_tdx_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tdx: Drop flags from __tdx_hypercall()
parents e54debe6 7a3a4018

arch/x86/boot/compressed/tdx.c

+2 −2
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ static inline unsigned int tdx_io_in(int size, u16 port) 
		.r14 = port,

	};



	if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT))

	if (__tdx_hypercall_ret(&args))

		return UINT_MAX;



	return args.r11;
@@ -43,7 +43,7 @@ static inline void tdx_io_out(int size, u16 port, u32 value) 
		.r15 = value,

	};



	__tdx_hypercall(&args, 0);

	__tdx_hypercall(&args);

}



static inline u8 tdx_inb(u16 port)

arch/x86/coco/tdx/tdcall.S

+38 −28
Original line number Diff line number Diff line
@@ -85,12 +85,12 @@ SYM_FUNC_START(__tdx_module_call) 
SYM_FUNC_END(__tdx_module_call)



/*

 * __tdx_hypercall() - Make hypercalls to a TDX VMM using TDVMCALL leaf

 * of TDCALL instruction

 * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDCALL

 * instruction

 *

 * Transforms values in  function call argument struct tdx_hypercall_args @args

 * into the TDCALL register ABI. After TDCALL operation, VMM output is saved

 * back in @args.

 * back in @args, if \ret is 1.

 *

 *-------------------------------------------------------------------------

 * TD VMCALL ABI:
@@ -105,26 +105,18 @@ SYM_FUNC_END(__tdx_module_call) 
 *                       specification. Non zero value indicates vendor

 *                       specific ABI.

 * R11                 - VMCALL sub function number

 * RBX, RBP, RDI, RSI  - Used to pass VMCALL sub function specific arguments.

 * RBX, RDX, RDI, RSI  - Used to pass VMCALL sub function specific arguments.

 * R8-R9, R12-R15      - Same as above.

 *

 * Output Registers:

 *

 * RAX                 - TDCALL instruction status (Not related to hypercall

 *                        output).

 * R10                 - Hypercall output error code.

 * R11-R15             - Hypercall sub function specific output values.

 * RBX, RDX, RDI, RSI  - Hypercall sub function specific output values.

 * R8-R15              - Same as above.

 *

 *-------------------------------------------------------------------------

 *

 * __tdx_hypercall() function ABI:

 *

 * @args  (RDI)        - struct tdx_hypercall_args for input and output

 * @flags (RSI)        - TDX_HCALL_* flags

 *

 * On successful completion, return the hypercall error code.

 */

SYM_FUNC_START(__tdx_hypercall)

.macro TDX_HYPERCALL ret:req

	FRAME_BEGIN



	/* Save callee-saved GPRs as mandated by the x86_64 ABI */
@@ -134,9 +126,8 @@ SYM_FUNC_START(__tdx_hypercall) 
	push %r12

	push %rbx



	/* Free RDI and RSI to be used as TDVMCALL arguments */

	/* Free RDI to be used as TDVMCALL arguments */

	movq %rdi, %rax

	push %rsi



	/* Copy hypercall registers from arg struct: */

	movq TDX_HYPERCALL_r8(%rax),  %r8
@@ -171,14 +162,11 @@ SYM_FUNC_START(__tdx_hypercall) 
	 * and are handled by callers.

	 */

	testq %rax, %rax

	jne .Lpanic

	jne .Lpanic\@



	pop %rax



	/* Copy hypercall result registers to arg struct if needed */

	testq $TDX_HCALL_HAS_OUTPUT, (%rsp)

	jz .Lout



	.if \ret

	movq %r8,  TDX_HYPERCALL_r8(%rax)

	movq %r9,  TDX_HYPERCALL_r9(%rax)

	movq %r10, TDX_HYPERCALL_r10(%rax)
@@ -191,7 +179,8 @@ SYM_FUNC_START(__tdx_hypercall) 
	movq %rsi, TDX_HYPERCALL_rsi(%rax)

	movq %rbx, TDX_HYPERCALL_rbx(%rax)

	movq %rdx, TDX_HYPERCALL_rdx(%rax)

.Lout:

	.endif



	/* TDVMCALL leaf return code is in R10 */

	movq %r10, %rax
@@ -208,9 +197,6 @@ SYM_FUNC_START(__tdx_hypercall) 
	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
@@ -221,9 +207,33 @@ SYM_FUNC_START(__tdx_hypercall) 
	FRAME_END



	RET

.Lpanic:

.Lpanic\@:

	call __tdx_hypercall_failed

	/* __tdx_hypercall_failed never returns */

	REACHABLE

	jmp .Lpanic

	jmp .Lpanic\@

.endm



/*

 *

 * __tdx_hypercall() function ABI:

 *

 * @args  (RDI)        - struct tdx_hypercall_args for input

 *

 * On successful completion, return the hypercall error code.

 */

SYM_FUNC_START(__tdx_hypercall)

	TDX_HYPERCALL ret=0

SYM_FUNC_END(__tdx_hypercall)



/*

 *

 * __tdx_hypercall_ret() function ABI:

 *

 * @args  (RDI)        - struct tdx_hypercall_args for input and output

 *

 * On successful completion, return the hypercall error code.

 */

SYM_FUNC_START(__tdx_hypercall_ret)

	TDX_HYPERCALL ret=1

SYM_FUNC_END(__tdx_hypercall_ret)

arch/x86/coco/tdx/tdx.c

+9 −9
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15) 
		.r15 = r15,

	};



	return __tdx_hypercall(&args, 0);

	return __tdx_hypercall(&args);

}



/* Called from __tdx_hypercall() for unrecoverable failure */
@@ -99,7 +99,7 @@ long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2, 
		.r14 = p4,

	};



	return __tdx_hypercall(&args, 0);

	return __tdx_hypercall(&args);

}

EXPORT_SYMBOL_GPL(tdx_kvm_hypercall);

#endif
@@ -179,7 +179,7 @@ static void __noreturn tdx_panic(const char *msg) 
	 * happens to return.

	 */

	while (1)

		__tdx_hypercall(&args, 0);

		__tdx_hypercall(&args);

}



static void tdx_parse_tdinfo(u64 *cc_mask)
@@ -289,7 +289,7 @@ static u64 __cpuidle __halt(const bool irq_disabled) 
	 * can keep the vCPU in virtual HLT, even if an IRQ is

	 * pending, without hanging/breaking the guest.

	 */

	return __tdx_hypercall(&args, 0);

	return __tdx_hypercall(&args);

}



static int handle_halt(struct ve_info *ve)
@@ -326,7 +326,7 @@ static int read_msr(struct pt_regs *regs, struct ve_info *ve) 
	 * can be found in TDX Guest-Host-Communication Interface

	 * (GHCI), section titled "TDG.VP.VMCALL<Instruction.RDMSR>".

	 */

	if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT))

	if (__tdx_hypercall_ret(&args))

		return -EIO;



	regs->ax = lower_32_bits(args.r11);
@@ -348,7 +348,7 @@ static int write_msr(struct pt_regs *regs, struct ve_info *ve) 
	 * can be found in TDX Guest-Host-Communication Interface

	 * (GHCI) section titled "TDG.VP.VMCALL<Instruction.WRMSR>".

	 */

	if (__tdx_hypercall(&args, 0))

	if (__tdx_hypercall(&args))

		return -EIO;



	return ve_instr_len(ve);
@@ -380,7 +380,7 @@ static int handle_cpuid(struct pt_regs *regs, struct ve_info *ve) 
	 * ABI can be found in TDX Guest-Host-Communication Interface

	 * (GHCI), section titled "VP.VMCALL<Instruction.CPUID>".

	 */

	if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT))

	if (__tdx_hypercall_ret(&args))

		return -EIO;



	/*
@@ -407,7 +407,7 @@ static bool mmio_read(int size, unsigned long addr, unsigned long *val) 
		.r15 = *val,

	};



	if (__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT))

	if (__tdx_hypercall_ret(&args))

		return false;

	*val = args.r11;

	return true;
@@ -541,7 +541,7 @@ static bool handle_in(struct pt_regs *regs, int size, int port) 
	 * in TDX Guest-Host-Communication Interface (GHCI) section titled

	 * "TDG.VP.VMCALL<Instruction.IO>".

	 */

	success = !__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);

	success = !__tdx_hypercall_ret(&args);



	/* Update part of the register affected by the emulated instruction */

	regs->ax &= ~mask;

arch/x86/include/asm/shared/tdx.h

+2 −3
Original line number Diff line number Diff line
@@ -7,8 +7,6 @@ 


#define TDX_HYPERCALL_STANDARD  0



#define TDX_HCALL_HAS_OUTPUT	BIT(0)



#define TDX_CPUID_LEAF_ID	0x21

#define TDX_IDENT		"IntelTDX    "
@@ -36,7 +34,8 @@ struct tdx_hypercall_args { 
};



/* Used to request services from the VMM */

u64 __tdx_hypercall(struct tdx_hypercall_args *args, unsigned long flags);

u64 __tdx_hypercall(struct tdx_hypercall_args *args);

u64 __tdx_hypercall_ret(struct tdx_hypercall_args *args);



/* Called from __tdx_hypercall() for unrecoverable failure */

void __tdx_hypercall_failed(void);