On Wed, 31 Mar 2021 at 09:59, Zenghui Yu <yuzenghui@xxxxxxxxxx> wrote: > > [+kvmarm, Marc] > > On 2021/3/12 0:59, Peter Maydell wrote: > > Currently we give all the v7-and-up CPUs a PMU with 4 counters. This > > means that we don't provide the 6 counters that are required by the > > Arm BSA (Base System Architecture) specification if the CPU supports > > the Virtualization extensions. > So I've tested it with kvm and I get the following error before > VM startup: > > "qemu-system-aarch64: Failed to retrieve host CPU features" > > > --- > > target/arm/cpu.h | 1 + > > target/arm/cpu64.c | 3 +++ > > target/arm/cpu_tcg.c | 5 +++++ > > target/arm/helper.c | 29 +++++++++++++++++------------ > > target/arm/kvm64.c | 2 ++ > > 5 files changed, 28 insertions(+), 12 deletions(-) > > [...] > > > diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c > > index dff85f6db94..581335e49d3 100644 > > --- a/target/arm/kvm64.c > > +++ b/target/arm/kvm64.c > > @@ -566,6 +566,8 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf) > > ARM64_SYS_REG(3, 0, 0, 7, 1)); > > err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64mmfr2, > > ARM64_SYS_REG(3, 0, 0, 7, 2)); > > + err |= read_sys_reg64(fdarray[2], &ahcf->isar.reset_pmcr_el0, > > + ARM64_SYS_REG(3, 3, 9, 12, 0)); > > Looks like we tried to access PMCR_EL0 *before* telling kvm that > KVM_ARM_VCPU_PMU_V3 feature should be supported, which is now > refused by kvm [*]. > > [*] https://git.kernel.org/torvalds/c/11663111cd49 Oops, that's embarrassing. I should have tested with KVM, and I forgot the PMU needs special enablement :-( I'm on holiday right now so I probably won't have time to look at a fix for rc2. I might just revert this commit. thanks -- PMM _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
