linux-kernel - [PATCH v2 22/24] kvm: arm64: Keep nVHE EL2 vector installed

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Message-Id: <20201116204318.63987-23-dbrazdil@google.com>
Date:   Mon, 16 Nov 2020 20:43:16 +0000
From:   David Brazdil <dbrazdil@...gle.com>
To:     kvmarm@...ts.cs.columbia.edu
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Dennis Zhou <dennis@...nel.org>,
        Tejun Heo <tj@...nel.org>, Christoph Lameter <cl@...ux.com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Quentin Perret <qperret@...gle.com>,
        Andrew Scull <ascull@...gle.com>,
        Andrew Walbran <qwandor@...gle.com>, kernel-team@...roid.com,
        David Brazdil <dbrazdil@...gle.com>
Subject: [PATCH v2 22/24] kvm: arm64: Keep nVHE EL2 vector installed

KVM by default keeps the stub vector installed and installs the nVHE
vector only briefly for init and later on demand. Change this policy
to install the vector at init and then never uninstall it if the kernel
was given the protected KVM command line parameter.

Signed-off-by: David Brazdil <dbrazdil@...gle.com>
---
 arch/arm64/kvm/arm.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 49d2474f2a80..45bc7a6b9e0b 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1443,7 +1443,8 @@ static void _kvm_arch_hardware_disable(void *discard)
 
 void kvm_arch_hardware_disable(void)
 {
-	_kvm_arch_hardware_disable(NULL);
+	if (!is_protected_kvm_enabled())
+		_kvm_arch_hardware_disable(NULL);
 }
 
 #ifdef CONFIG_CPU_PM
@@ -1486,11 +1487,13 @@ static struct notifier_block hyp_init_cpu_pm_nb = {
 
 static void __init hyp_cpu_pm_init(void)
 {
-	cpu_pm_register_notifier(&hyp_init_cpu_pm_nb);
+	if (!is_protected_kvm_enabled())
+		cpu_pm_register_notifier(&hyp_init_cpu_pm_nb);
 }
 static void __init hyp_cpu_pm_exit(void)
 {
-	cpu_pm_unregister_notifier(&hyp_init_cpu_pm_nb);
+	if (!is_protected_kvm_enabled())
+		cpu_pm_unregister_notifier(&hyp_init_cpu_pm_nb);
 }
 #else
 static inline void hyp_cpu_pm_init(void)
@@ -1575,7 +1578,8 @@ static int init_subsystems(void)
 	kvm_coproc_table_init();
 
 out:
-	on_each_cpu(_kvm_arch_hardware_disable, NULL, 1);
+	if (err || !is_protected_kvm_enabled())
+		on_each_cpu(_kvm_arch_hardware_disable, NULL, 1);
 
 	return err;
 }
-- 
2.29.2.299.gdc1121823c-goog