From: Marc Zyngier maz@kernel.org
mainline inclusion from mainline-v5.14-rc1 commit d0c94c49792cf780cbfefe29f81bb8c3b73bc76b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4NP0K CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
-------------------
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@ama... Signed-off-by: Jingyi Wang wangjingyi11@huawei.com Reviewed-by: Zenghui Yu yuzenghui@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/arm.c | 4 ++++ arch/arm64/kvm/pmu-emul.c | 3 +++ 3 files changed, 8 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index fcd8cc7d3cb0..93cdc5a2fc97 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -47,6 +47,7 @@ #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 7f64131641a4..3ae13ef0c980 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -713,6 +713,10 @@ 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 00bf8733e718..597d0ed84086 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -858,6 +858,9 @@ int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu) kvm_pmu_vcpu_reset(vcpu); vcpu->arch.pmu.ready = true;
+ /* One-off reload of the PMU on first run */ + kvm_make_request(KVM_REQ_RELOAD_PMU, vcpu); + return 0; }