Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Marc Zyngier <maz@kernel.org>
To:     Quentin Perret <qperret@google.com>
Cc:     catalin.marinas@arm.com, james.morse@arm.com,
        julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com,
        android-kvm@google.com, seanjc@google.com, mate.toth-pal@arm.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
        tabba@google.com, ardb@kernel.org, mark.rutland@arm.com,
        dbrazdil@google.com
Subject: [PATCH v2 1/3] KVM: arm64: Constraint KVM's own __flush_dcache_area to protectected mode
Date:   Mon, 22 Mar 2021 17:56:37 +0000
Message-Id: <20210322175639.801566-2-maz@kernel.org>
In-Reply-To: <20210322175639.801566-1-maz@kernel.org>
References: <20210322175639.801566-1-maz@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

As we are about to specialise KVM's version of __flush_dcache_area
via a hack on the read_ctr macro, make sure that we won't ever
use KVM's copy of __flush_dcache_area(), as things would otherwise
break for late arriving CPUs.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/nvhe/cache.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/hyp/nvhe/cache.S b/arch/arm64/kvm/hyp/nvhe/cache.S
index 36cef6915428..1c177d3ec5c6 100644
--- a/arch/arm64/kvm/hyp/nvhe/cache.S
+++ b/arch/arm64/kvm/hyp/nvhe/cache.S
@@ -6,8 +6,12 @@
 #include <linux/linkage.h>
 #include <asm/assembler.h>
 #include <asm/alternative.h>
+#include <asm/asm-bug.h>
 
 SYM_FUNC_START_PI(__flush_dcache_area)
+alternative_if_not ARM64_KVM_PROTECTED_MODE
+	ASM_BUG()
+alternative_else_nop_endif
 	dcache_by_line_op civac, sy, x0, x1, x2, x3
 	ret
 SYM_FUNC_END_PI(__flush_dcache_area)
-- 
2.29.2