From 0ff1abf0f2027b3deab4196e4fe73e345fff3c7e Mon Sep 17 00:00:00 2001
From: Andrew Murray <andrew.murray@arm.com>
Date: Wed, 14 Sep 2022 11:45:56 +0800
Subject: [PATCH] KVM: arm64: Write arch.mdcr_el2 changes since last vcpu_load
on VHE
mainline inclusion
from mainline-v5.6
commit 4942dc6638b07b5326b6d2faa142635c559e7cd5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5QR6C
CVE: NA
-------------
On VHE systems arch.mdcr_el2 is written to mdcr_el2 at vcpu_load time to
set options for self-hosted debug and the performance monitors
extension.
Unfortunately the value of arch.mdcr_el2 is not calculated until
kvm_arm_setup_debug() in the run loop after the vcpu has been loaded.
This means that the initial brief iterations of the run loop use a zero
value of mdcr_el2 - until the vcpu is preempted. This also results in a
delay between changes to vcpu->guest_debug taking effect.
Fix this by writing to mdcr_el2 in kvm_arm_setup_debug() on VHE systems
when a change to arch.mdcr_el2 has been detected.
Fixes: d5a21bcc2995 ("KVM: arm64: Move common VHE/non-VHE trap config in separate functions")
Cc: <stable@vger.kernel.org> # 4.17.x-
Suggested-by: James Morse <james.morse@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Zengruan Ye <yezengruan@huawei.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
---
arch/arm64/kvm/debug.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index 00d422336a45..4e722d73a3c3 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -112,7 +112,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
{
bool trap_debug = !(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY);
- unsigned long mdscr;
+ unsigned long mdscr, orig_mdcr_el2 = vcpu->arch.mdcr_el2;
trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
@@ -208,6 +208,10 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
if (vcpu_read_sys_reg(vcpu, MDSCR_EL1) & (DBG_MDSCR_KDE | DBG_MDSCR_MDE))
vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
+ /* Write mdcr_el2 changes since vcpu_load on VHE systems */
+ if (has_vhe() && orig_mdcr_el2 != vcpu->arch.mdcr_el2)
+ write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
+
trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_read_sys_reg(vcpu, MDSCR_EL1));
}
--
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