From:   Suzuki K Poulose <suzuki.poulose@arm.com>
To:     kvm@vger.kernel.org, kvmarm@lists.linux.dev
Cc:     suzuki.poulose@arm.com,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Andrew Jones <andrew.jones@linux.dev>,
        Christoffer Dall <christoffer.dall@arm.com>,
        Fuad Tabba <tabba@google.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Joey Gouly <Joey.Gouly@arm.com>, Marc Zyngier <maz@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Steven Price <steven.price@arm.com>,
        Thomas Huth <thuth@redhat.com>, Will Deacon <will@kernel.org>,
        Zenghui Yu <yuzenghui@huawei.com>, linux-coco@lists.linux.dev,
        kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: [RFC kvmtool 28/31] arm64: realm: Enforce virtio F_ACCESS_PLATFORM flag
Date:   Fri, 27 Jan 2023 11:39:29 +0000
Message-Id: <20230127113932.166089-29-suzuki.poulose@arm.com>
In-Reply-To: <20230127113932.166089-1-suzuki.poulose@arm.com>
References: <20230127112248.136810-1-suzuki.poulose@arm.com>
 <20230127113932.166089-1-suzuki.poulose@arm.com>
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For realms, force the F_ACCESS_PLATFORM flag to ensure DMA-APIs
are triggered for virtio in Linux

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arm/aarch64/kvm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c
index a4664237..1f3a0def 100644
--- a/arm/aarch64/kvm.c
+++ b/arm/aarch64/kvm.c
@@ -5,6 +5,7 @@
 #include <linux/byteorder.h>
 #include <linux/cpumask.h>
 #include <linux/sizes.h>
+#include <linux/virtio_config.h>
 
 #include <kvm/util.h>
 
@@ -237,5 +238,10 @@ void kvm__arch_enable_mte(struct kvm *kvm)
 
 u64 kvm__arch_get_virtio_host_features(struct kvm *kvm)
 {
-	return 0;
+	u64 features = 0;
+
+	/* Enforce F_ACCESS_PLATFORM for Realms */
+	if (kvm->cfg.arch.is_realm)
+		features |= (1ULL << VIRTIO_F_ACCESS_PLATFORM);
+	return features;
 }
-- 
2.34.1