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Subject[PATCH] x86/paravirt: Fix build PARAVIRT_XXL=y without XEN_PV
Date
TDX is going to use CONFIG_PARAVIRT_XXL, but kernel fails to compile if
XEN_PV is not enabled:

ld.lld: error: undefined symbol: xen_iret

It happens because INTERRUPT_RETURN defined to use xen_iret if
CONFIG_PARAVIRT_XXL enabled regardless of CONFIG_XEN_PV.

The issue is not visible in the current kernel because CONFIG_XEN_PV is
the only user of CONFIG_PARAVIRT_XXL and there's no way to enable them
separately.

Rework code to define INTERRUPT_RETURN based on CONFIG_XEN_PV, not
CONFIG_PARAVIRT_XXL.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Deep Shah <sdeep@vmware.com>
Cc: "VMware, Inc." <pv-drivers@vmware.com>
---
arch/x86/include/asm/irqflags.h | 7 +++++--
arch/x86/include/asm/paravirt.h | 5 -----
2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index b794b6da3214..3b8ddcb7be76 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -118,8 +118,6 @@ static __always_inline unsigned long arch_local_irq_save(void)
#define SAVE_FLAGS pushfq; popq %rax
#endif

-#define INTERRUPT_RETURN jmp native_iret
-
#endif

#endif /* __ASSEMBLY__ */
@@ -147,8 +145,13 @@ static __always_inline void arch_local_irq_restore(unsigned long flags)
#ifdef CONFIG_X86_64
#ifdef CONFIG_XEN_PV
#define SWAPGS ALTERNATIVE "swapgs", "", X86_FEATURE_XENPV
+#define INTERRUPT_RETURN \
+ ANNOTATE_RETPOLINE_SAFE; \
+ ALTERNATIVE_TERNARY("jmp *paravirt_iret(%rip);", \
+ X86_FEATURE_XENPV, "jmp xen_iret;", "jmp native_iret;")
#else
#define SWAPGS swapgs
+#define INTERRUPT_RETURN jmp native_iret
#endif
#endif
#endif /* !__ASSEMBLY__ */
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 8e04268d7c10..865f78635af1 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -745,11 +745,6 @@ extern void default_banner(void);
#define PARA_SITE(ptype, ops) _PVSITE(ptype, ops, .quad, 8)
#define PARA_INDIRECT(addr) *addr(%rip)

-#define INTERRUPT_RETURN \
- ANNOTATE_RETPOLINE_SAFE; \
- ALTERNATIVE_TERNARY("jmp *paravirt_iret(%rip);", \
- X86_FEATURE_XENPV, "jmp xen_iret;", "jmp native_iret;")
-
#ifdef CONFIG_DEBUG_ENTRY
.macro PARA_IRQ_save_fl
PARA_SITE(PARA_PATCH(PV_IRQ_save_fl),
--
2.32.0
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