linux-kernel - [PATCH 5/9] KVM: arm/arm64: vgic-its: Check GITS_CBASER validity before processing commands

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Date:   Mon, 25 Sep 2017 15:34:34 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        marc.zyngier@....com, cdall@...aro.org, peter.maydell@...aro.org,
        andre.przywara@....com, wanghaibin.wang@...wei.com
Cc:     wu.wubin@...wei.com
Subject: [PATCH 5/9] KVM: arm/arm64: vgic-its: Check GITS_CBASER validity before processing commands

At the moment vgic_its_process_commands() does not
check the CBASER is valid before processing any command.
Let's fix that.

Also rename cbaser local variable into cbaser_pa to avoid
any confusion with the full register.

Signed-off-by: Eric Auger <eric.auger@...hat.com>
---
 virt/kvm/arm/vgic/vgic-its.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 60ecf91..720552c 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1301,17 +1301,20 @@ static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its,
 /* Must be called with the cmd_lock held. */
 static void vgic_its_process_commands(struct kvm *kvm, struct vgic_its *its)
 {
-	gpa_t cbaser;
+	gpa_t cbaser_pa;
 	u64 cmd_buf[4];
 
-	/* Commands are only processed when the ITS is enabled. */
-	if (!its->enabled)
+	/*
+	 * Commands are only processed when the ITS is enabled and
+	 * CBASER is valid
+	 */
+	if (!its->enabled || (!(its->cbaser & GITS_CBASER_VALID)))
 		return;
 
-	cbaser = CBASER_ADDRESS(its->cbaser);
+	cbaser_pa = CBASER_ADDRESS(its->cbaser);
 
 	while (its->cwriter != its->creadr) {
-		int ret = kvm_read_guest(kvm, cbaser + its->creadr,
+		int ret = kvm_read_guest(kvm, cbaser_pa + its->creadr,
 					 cmd_buf, ITS_CMD_SIZE);
 		/*
 		 * If kvm_read_guest() fails, this could be due to the guest
-- 
2.5.5