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x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT

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CONFIG_PARAVIRT_XXL is mainly defined/used by XEN PV guests. For
other VM guest types, features supported under CONFIG_PARAVIRT
are self sufficient. CONFIG_PARAVIRT mainly provides support for
TLB flush operations and time related operations.

For TDX guest as well, paravirt calls under CONFIG_PARVIRT meets
most of its requirement except the need of HLT and SAFE_HLT
paravirt calls, which is currently defined under
CONFIG_PARAVIRT_XXL.

Since enabling CONFIG_PARAVIRT_XXL is too bloated for TDX guest
like platforms, move HLT and SAFE_HLT paravirt calls under
CONFIG_PARAVIRT.

Moving HLT and SAFE_HLT paravirt calls are not fatal and should not
break any functionality for current users of CONFIG_PARAVIRT.

Fixes: bfe6ed0c67 ("x86/tdx: Add HLT support for TDX guests")
Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Tested-by: Ryan Afranji <afranji@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20250228014416.3925664-2-vannapurve@google.com
This commit is contained in:
Kirill A. Shutemov 2025-02-28 01:44:14 +00:00 • committed by Ingo Molnar
parent 0d86c23953
commit 22cc5ca5de
4 changed files with 41 additions and 36 deletions
Download patch file Download diff file Expand all files Collapse all files

40
arch/x86/include/asm/irqflags.h
View file

@ -76,6 +76,28 @@ static __always_inline void native_local_irq_restore(unsigned long flags)
#endif
#ifndef CONFIG_PARAVIRT
#ifndef __ASSEMBLY__
/*
* Used in the idle loop; sti takes one instruction cycle
* to complete:
*/
static __always_inline void arch_safe_halt(void)
{
native_safe_halt();
}
/*
* Used when interrupts are already enabled or to
* shutdown the processor:
*/
static __always_inline void halt(void)
{
native_halt();
}
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_PARAVIRT */
#ifdef CONFIG_PARAVIRT_XXL
#include <asm/paravirt.h>
#else
@ -97,24 +119,6 @@ static __always_inline void arch_local_irq_enable(void)
native_irq_enable();
}
/*
* Used in the idle loop; sti takes one instruction cycle
* to complete:
*/
static __always_inline void arch_safe_halt(void)
{
native_safe_halt();
}
/*
* Used when interrupts are already enabled or to
* shutdown the processor:
*/
static __always_inline void halt(void)
{
native_halt();
}
/*
* For spinlocks, etc:
*/

20
arch/x86/include/asm/paravirt.h
View file

@ -102,6 +102,16 @@ static inline void notify_page_enc_status_changed(unsigned long pfn,
PVOP_VCALL3(mmu.notify_page_enc_status_changed, pfn, npages, enc);
}
static __always_inline void arch_safe_halt(void)
{
PVOP_VCALL0(irq.safe_halt);
}
static inline void halt(void)
{
PVOP_VCALL0(irq.halt);
}
#ifdef CONFIG_PARAVIRT_XXL
static inline void load_sp0(unsigned long sp0)
{
@ -165,16 +175,6 @@ static inline void __write_cr4(unsigned long x)
PVOP_VCALL1(cpu.write_cr4, x);
}
static __always_inline void arch_safe_halt(void)
{
PVOP_VCALL0(irq.safe_halt);
}
static inline void halt(void)
{
PVOP_VCALL0(irq.halt);
}
static inline u64 paravirt_read_msr(unsigned msr)
{
return PVOP_CALL1(u64, cpu.read_msr, msr);

3
arch/x86/include/asm/paravirt_types.h
View file

@ -120,10 +120,9 @@ struct pv_irq_ops {
struct paravirt_callee_save save_fl;
struct paravirt_callee_save irq_disable;
struct paravirt_callee_save irq_enable;
#endif
void (*safe_halt)(void);
void (*halt)(void);
#endif
} __no_randomize_layout;
struct pv_mmu_ops {

14
arch/x86/kernel/paravirt.c
View file

@ -75,6 +75,11 @@ void paravirt_set_sched_clock(u64 (*func)(void))
static_call_update(pv_sched_clock, func);
}
static noinstr void pv_native_safe_halt(void)
{
native_safe_halt();
}
#ifdef CONFIG_PARAVIRT_XXL
static noinstr void pv_native_write_cr2(unsigned long val)
{
@ -100,11 +105,6 @@ static noinstr void pv_native_set_debugreg(int regno, unsigned long val)
{
native_set_debugreg(regno, val);
}
static noinstr void pv_native_safe_halt(void)
{
native_safe_halt();
}
#endif
struct pv_info pv_info = {
@ -161,9 +161,11 @@ struct paravirt_patch_template pv_ops = {
.irq.save_fl = __PV_IS_CALLEE_SAVE(pv_native_save_fl),
.irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable),
.irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable),
#endif /* CONFIG_PARAVIRT_XXL */
/* Irq HLT ops. */
.irq.safe_halt = pv_native_safe_halt,
.irq.halt = native_halt,
#endif /* CONFIG_PARAVIRT_XXL */
/* Mmu ops. */
.mmu.flush_tlb_user = native_flush_tlb_local,