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| author | Marc Zyngier <maz@kernel.org> | 2021-06-03 18:50:02 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-14 17:59:21 +0300 |
| commit | ef33252d3dd1d8f6eeed462059c8275f910a5f1d (patch) | |
| tree | d35cb00d0bf1b70a218d9a41c7941f68e8e0df5c | |
| parent | 670fe6001d50e1e676756802ed8ead347458b050 (diff) | |
| download | linux-ef33252d3dd1d8f6eeed462059c8275f910a5f1d.tar.xz | |
KVM: arm64: Restore PMU configuration on first run
[ Upstream commit d0c94c49792cf780cbfefe29f81bb8c3b73bc76b ]
Restoring a guest with an active virtual PMU results in no perf
counters being instanciated on the host side. Not quite what
you'd expect from a restore.
In order to fix this, force a writeback of PMCR_EL0 on the first
run of a vcpu (using a new request so that it happens once the
vcpu has been loaded). This will in turn create all the host-side
counters that were missing.
Reported-by: Jinank Jain <jinankj@amazon.de>
Tested-by: Jinank Jain <jinankj@amazon.de>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/87wnrbylxv.wl-maz@kernel.org
Link: https://lore.kernel.org/r/b53dfcf9bbc4db7f96154b1cd5188d72b9766358.camel@amazon.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/arm.c | 4 | ||||
| -rw-r--r-- | arch/arm64/kvm/pmu-emul.c | 3 |
3 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 858c2fcfc043..4e4356add46e 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -46,6 +46,7 @@ #define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2) #define KVM_REQ_RECORD_STEAL KVM_ARCH_REQ(3) #define KVM_REQ_RELOAD_GICv4 KVM_ARCH_REQ(4) +#define KVM_REQ_RELOAD_PMU KVM_ARCH_REQ(5) #define KVM_DIRTY_LOG_MANUAL_CAPS (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE | \ KVM_DIRTY_LOG_INITIALLY_SET) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7730b81aad6d..8455c5c30116 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -684,6 +684,10 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu) vgic_v4_load(vcpu); preempt_enable(); } + + if (kvm_check_request(KVM_REQ_RELOAD_PMU, vcpu)) + kvm_pmu_handle_pmcr(vcpu, + __vcpu_sys_reg(vcpu, PMCR_EL0)); } } diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index e32c6e139a09..e9699d10d2bd 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -850,6 +850,9 @@ int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu) return -EINVAL; } + /* One-off reload of the PMU on first run */ + kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu); + return 0; } |