linux-kernel - [PATCH 4.12 33/84] KVM: ARM64: fix phy counter access failure in guest.

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Date:   Wed, 19 Jul 2017 11:43:39 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hu Huajun <huhuajun@...wei.com>,
        Christoffer Dall <cdall@...aro.org>,
        Marc Zyngier <marc.zyngier@....com>
Subject: [PATCH 4.12 33/84] KVM: ARM64: fix phy counter access failure in guest.

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hu Huajun <huhuajun@...wei.com>

commit 02d50cdaff36c135d222015cffdca3ff11d168ea upstream.

When reading the cntpct_el0 in guest with VHE (Virtual Host Extension)
enabled in host, the "Unsupported guest sys_reg access" error reported.
The reason is cnthctl_el2.EL1PCTEN is not enabled, which is expected
to be done in kvm_timer_init_vhe(). The problem is kvm_timer_init_vhe
is called by cpu_init_hyp_mode, and which is called when VHE is disabled.
This patch remove the incorrect call to kvm_timer_init_vhe() from
cpu_init_hyp_mode(), and calls kvm_timer_init_vhe() to enable
cnthctl_el2.EL1PCTEN in cpu_hyp_reinit().

Fixes: 488f94d7212b ("KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems")
Signed-off-by: Hu Huajun <huhuajun@...wei.com>
Reviewed-by: Christoffer Dall <cdall@...aro.org>
Acked-by: Marc Zyngier <marc.zyngier@....com>
Signed-off-by: Christoffer Dall <cdall@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 virt/kvm/arm/arm.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1115,9 +1115,6 @@ static void cpu_init_hyp_mode(void *dumm
 	__cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr);
 	__cpu_init_stage2();
 
-	if (is_kernel_in_hyp_mode())
-		kvm_timer_init_vhe();
-
 	kvm_arm_init_debug();
 }
 
@@ -1137,6 +1134,7 @@ static void cpu_hyp_reinit(void)
 		 * event was cancelled before the CPU was reset.
 		 */
 		__cpu_init_stage2();
+		kvm_timer_init_vhe();
 	} else {
 		cpu_init_hyp_mode(NULL);
 	}