linux-kernel - [PATCH v2 01/15] KVM: arm64: Check if running in VHE from kvm_host_owns_hyp

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Message-Id: <20211019121304.2732332-2-qperret@google.com>
Date:   Tue, 19 Oct 2021 13:12:50 +0100
From:   Quentin Perret <qperret@...gle.com>
To:     Marc Zyngier <maz@...nel.org>, James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Fuad Tabba <tabba@...gle.com>,
        David Brazdil <dbrazdil@...gle.com>,
        Andrew Walbran <qwandor@...gle.com>
Cc:     linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org, kernel-team@...roid.com,
        qperret@...gle.com
Subject: [PATCH v2 01/15] KVM: arm64: Check if running in VHE from kvm_host_owns_hyp_mappings()

The kvm_host_owns_hyp_mappings() function should return true if and only
if the host kernel is responsible for creating the hypervisor stage-1
mappings. That is only possible in standard non-VHE mode, or during boot
in protected nVHE mode. But either way, non of this makes sense in VHE,
so make sure to catch this case as well, hence making the function
return sensible values in any context (VHE or not).

Suggested-by: Marc Zyngier <maz@...nel.org>
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
 arch/arm64/kvm/mmu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index da10996dcdf1..0019b2309f70 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -239,6 +239,9 @@ void free_hyp_pgds(void)
 
 static bool kvm_host_owns_hyp_mappings(void)
 {
+	if (is_kernel_in_hyp_mode())
+		return false;
+
 	if (static_branch_likely(&kvm_protected_mode_initialized))
 		return false;
 
-- 
2.33.0.1079.g6e70778dc9-goog