linux-kernel - [tip: x86/sev] x86/irqflags: Provide native versions of the local_irq

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Date: Tue, 18 Jun 2024 09:45:01 -0000
From: "tip-bot2 for Tom Lendacky" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Tom Lendacky <thomas.lendacky@....com>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/sev] x86/irqflags: Provide native versions of the
 local_irq_save()/restore()

The following commit has been merged into the x86/sev branch of tip:

Commit-ID:     b547fc2c9927a95808ef93d7fbd5dd70679fb501
Gitweb:        https://git.kernel.org/tip/b547fc2c9927a95808ef93d7fbd5dd70679fb501
Author:        Tom Lendacky <thomas.lendacky@....com>
AuthorDate:    Wed, 05 Jun 2024 10:18:44 -05:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 11 Jun 2024 07:22:46 +02:00

x86/irqflags: Provide native versions of the local_irq_save()/restore()

Functions that need to disable IRQs, but are common to both early boot and
post-boot execution, are unable to deal with paravirt support associated
with local_irq_save() and local_irq_restore().

Create native versions of these for use in these situations.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/c4c33c0d07200164a3dd8cfd6da0344f57732648.1717600736.git.thomas.lendacky@amd.com
---
 arch/x86/include/asm/irqflags.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h
index 8c5ae64..cf7fc2b 100644
--- a/arch/x86/include/asm/irqflags.h
+++ b/arch/x86/include/asm/irqflags.h
@@ -54,6 +54,26 @@ static __always_inline void native_halt(void)
 	asm volatile("hlt": : :"memory");
 }
 
+static __always_inline int native_irqs_disabled_flags(unsigned long flags)
+{
+	return !(flags & X86_EFLAGS_IF);
+}
+
+static __always_inline unsigned long native_local_irq_save(void)
+{
+	unsigned long flags = native_save_fl();
+
+	native_irq_disable();
+
+	return flags;
+}
+
+static __always_inline void native_local_irq_restore(unsigned long flags)
+{
+	if (!native_irqs_disabled_flags(flags))
+		native_irq_enable();
+}
+
 #endif
 
 #ifdef CONFIG_PARAVIRT_XXL