Commit e4143b60 authored by Andrew Murray's avatar Andrew Murray Committed by Greg Kroah-Hartman
Browse files

KVM: arm64: Write arch.mdcr_el2 changes since last vcpu_load on VHE

commit 4942dc66 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: d5a21bcc

 ("KVM: arm64: Move common VHE/non-VHE trap config in separate functions")
Cc: <stable@vger.kernel.org> # 4.17.x-
Suggested-by: default avatarJames Morse <james.morse@arm.com>
Acked-by: default avatarWill Deacon <will@kernel.org>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarAndrew Murray <andrew.murray@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f387897c
......@@ -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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