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x86/entry: Zap the #VC entry user and kernel macros

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Drop the separate kernel and user macros in favor of calling a single #VC
C handler which multiplexes between the kernel and user #VC entry points
by looking at CS's RPL.

Zap unused DEFINE_IDTENTRY_VC while at it.

There should be no functionality change resulting from this - just code
simplification.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A. Dadhania <nikunj@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Tested-by: Nikunj A. Dadhania <nikunj@amd.com>
Link: https://patch.msgid.link/20260420164352.32129-1-bp@kernel.org
This commit is contained in:
Borislav Petkov (AMD) 2026-04-20 18:43:52 +02:00
parent 7fd2df204f
commit 52705e72e2
5 changed files with 18 additions and 40 deletions
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3
arch/x86/coco/sev/internal.h
View File

@ -70,6 +70,9 @@ void svsm_pval_pages(struct snp_psc_desc *desc);
int svsm_perform_call_protocol(struct svsm_call *call);
bool snp_svsm_vtpm_probe(void);
noinstr void kernel_exc_vmm_communication(struct pt_regs *regs, unsigned long error_code);
noinstr void user_exc_vmm_communication(struct pt_regs *regs, unsigned long error_code);
static inline u64 sev_es_rd_ghcb_msr(void)
{
return native_rdmsrq(MSR_AMD64_SEV_ES_GHCB);

12
arch/x86/coco/sev/vc-handle.c
View File

@ -954,7 +954,7 @@ static __always_inline bool vc_is_db(unsigned long error_code)
* Runtime #VC exception handler when raised from kernel mode. Runs in NMI mode
* and will panic when an error happens.
*/
DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
noinstr void kernel_exc_vmm_communication(struct pt_regs *regs, unsigned long error_code)
{
irqentry_state_t irq_state;
@ -1006,7 +1006,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
* Runtime #VC exception handler when raised from user mode. Runs in IRQ mode
* and will kill the current task with SIGBUS when an error happens.
*/
DEFINE_IDTENTRY_VC_USER(exc_vmm_communication)
noinstr void user_exc_vmm_communication(struct pt_regs *regs, unsigned long error_code)
{
/*
* Handle #DB before calling into !noinstr code to avoid recursive #DB.
@ -1032,6 +1032,14 @@ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication)
irqentry_exit_to_user_mode(regs);
}
DEFINE_IDTENTRY_RAW_ERRORCODE(exc_vmm_communication)
{
if (user_mode(regs))
return user_exc_vmm_communication(regs, error_code);
else
return kernel_exc_vmm_communication(regs, error_code);
}
bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
{
unsigned long exit_code = regs->orig_ax;

4
arch/x86/entry/entry_64.S
View File

@ -492,7 +492,7 @@ SYM_CODE_START(\asmsym)
movq %rsp, %rdi /* pt_regs pointer */
call kernel_\cfunc
call \cfunc
/*
* No need to switch back to the IST stack. The current stack is either
@ -503,7 +503,7 @@ SYM_CODE_START(\asmsym)
/* Switch to the regular task stack */
.Lfrom_usermode_switch_stack_\@:
idtentry_body user_\cfunc, has_error_code=1
idtentry_body \cfunc, has_error_code=1
_ASM_NOKPROBE(\asmsym)
SYM_CODE_END(\asmsym)

10
arch/x86/entry/entry_fred.c
View File

@ -177,16 +177,6 @@ static noinstr void fred_extint(struct pt_regs *regs)
}
}
#ifdef CONFIG_AMD_MEM_ENCRYPT
noinstr void exc_vmm_communication(struct pt_regs *regs, unsigned long error_code)
{
if (user_mode(regs))
return user_exc_vmm_communication(regs, error_code);
else
return kernel_exc_vmm_communication(regs, error_code);
}
#endif
static noinstr void fred_hwexc(struct pt_regs *regs, unsigned long error_code)
{
/* Optimize for #PF. That's the only exception which matters performance wise */

29
arch/x86/include/asm/idtentry.h
View File

@ -340,17 +340,14 @@ static __always_inline void __##func(struct pt_regs *regs)
__visible void noist_##func(struct pt_regs *regs)
/**
* DECLARE_IDTENTRY_VC - Declare functions for the VC entry point
* DECLARE_IDTENTRY_VC - Declare a function for the VC entry point
* @vector: Vector number (ignored for C)
* @func: Function name of the entry point
*
* Maps to DECLARE_IDTENTRY_RAW_ERRORCODE, but declares also the
* safe_stack C handler.
* Maps to DECLARE_IDTENTRY_RAW_ERRORCODE.
*/
#define DECLARE_IDTENTRY_VC(vector, func) \
DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func); \
__visible noinstr void kernel_##func(struct pt_regs *regs, unsigned long error_code); \
__visible noinstr void user_##func(struct pt_regs *regs, unsigned long error_code)
DECLARE_IDTENTRY_RAW_ERRORCODE(vector, func);
/**
* DEFINE_IDTENTRY_IST - Emit code for IST entry points
@ -391,26 +388,6 @@ static __always_inline void __##func(struct pt_regs *regs)
#define DEFINE_IDTENTRY_DF(func) \
DEFINE_IDTENTRY_RAW_ERRORCODE(func)
/**
* DEFINE_IDTENTRY_VC_KERNEL - Emit code for VMM communication handler
* when raised from kernel mode
* @func: Function name of the entry point
*
* Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
*/
#define DEFINE_IDTENTRY_VC_KERNEL(func) \
DEFINE_IDTENTRY_RAW_ERRORCODE(kernel_##func)
/**
* DEFINE_IDTENTRY_VC_USER - Emit code for VMM communication handler
* when raised from user mode
* @func: Function name of the entry point
*
* Maps to DEFINE_IDTENTRY_RAW_ERRORCODE
*/
#define DEFINE_IDTENTRY_VC_USER(func) \
DEFINE_IDTENTRY_RAW_ERRORCODE(user_##func)
#else /* CONFIG_X86_64 */
/**