linux-kernel - [PATCH v3 4/7] x86/sev-es: Run #VC handler in plain IRQ state

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Date:   Tue,  8 Jun 2021 11:54:36 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     x86@...nel.org
Cc:     Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
        hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jiri Slaby <jslaby@...e.cz>,
        Dan Williams <dan.j.williams@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Juergen Gross <jgross@...e.com>,
        Kees Cook <keescook@...omium.org>,
        David Rientjes <rientjes@...gle.com>,
        Cfir Cohen <cfir@...gle.com>,
        Erdem Aktas <erdemaktas@...gle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mike Stunes <mstunes@...are.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Martin Radev <martin.b.radev@...il.com>,
        Arvind Sankar <nivedita@...m.mit.edu>,
        linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org
Subject: [PATCH v3 4/7] x86/sev-es: Run #VC handler in plain IRQ state

From: Joerg Roedel <jroedel@...e.de>

Use irqentry_enter() and irqentry_exit() to track the runtime state of
the #VC handler. The reason it ran in NMI mode was solely to make sure
nothing interrupts the handler while the GHCB is in use.

This is handled now in sev_es_get/put_ghcb() directly, so there is no
reason the #VC handler can not run in normal IRQ mode and enjoy the
benefits like being able to send signals.

Fixes: 62441a1fb532 ("x86/sev-es: Correctly track IRQ states in runtime #VC handler")
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 arch/x86/kernel/sev.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 2a922d1b03c8..b563fb747aed 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1354,8 +1354,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
 		return;
 	}
 
-	irq_state = irqentry_nmi_enter(regs);
-	lockdep_assert_irqs_disabled();
+	irq_state = irqentry_enter(regs);
 	instrumentation_begin();
 
 	/*
@@ -1408,7 +1407,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
 
 out:
 	instrumentation_end();
-	irqentry_nmi_exit(regs, irq_state);
+	irqentry_exit(regs, irq_state);
 
 	return;
 
-- 
2.31.1