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| author |   Andrew Murray <andrew.murray@arm.com> | 2020-01-17 13:43:24 +0000 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2020-01-22 18:38:04 +0000 |
| commit | 4942dc6638b07b5326b6d2faa142635c559e7cd5 (patch) | |
| tree | 7bcc444ca4f3d2dd63e0176d28b7a8b1596deae4 /arch/arm64/kvm | |
| parent | Linux 5.5-rc7 (diff) | |
| download | linux-dev-4942dc6638b07b5326b6d2faa142635c559e7cd5.tar.xz linux-dev-4942dc6638b07b5326b6d2faa142635c559e7cd5.zip | |
KVM: arm64: Write arch.mdcr_el2 changes since last vcpu_load on VHE
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>
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/debug.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 43487f035385..7a7e425616b5 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -101,7 +101,7 @@ 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); @@ -197,6 +197,10 @@ 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)); } |