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authorAndrew Murray <andrew.murray@arm.com>2020-01-17 13:43:24 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-02-01 09:37:12 +0000
commite4143b60ae6b2eee83f4eee4db4d5c30890bcbe1 (patch)
tree707071c114e0c28bd8c2fbf4c4119d248e413080
parentf387897cf5b8cad1313c683419f53cdbabc9f092 (diff)
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KVM: arm64: Write arch.mdcr_el2 changes since last vcpu_load on VHE
commit 4942dc6638b07b5326b6d2faa142635c559e7cd5 upstream. 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm64/kvm/debug.c6
1 files changed, 5 insertions, 1 deletions
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));
}