| Message ID | 20230819043947.4100985-1-reijiw@google.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | KVM: arm64: PMU: Fix PMUver related handling of vPMU support | expand |
On Fri, 18 Aug 2023 21:39:43 -0700, Reiji Watanabe wrote: > This series fixes a couple of PMUver related handling of > vPMU support. > > On systems where the PMUVer is not uniform across all PEs, > KVM currently does not advertise PMUv3 to the guest, > even if userspace successfully runs KVM_ARM_VCPU_INIT with > KVM_ARM_VCPU_PMU_V3. > > [...] Applied to next, thanks! [1/4] KVM: arm64: PMU: Disallow vPMU on non-uniform PMUVer commit: ec3eb9ed6081bea8ebf603ff545dba127071b928 [2/4] KVM: arm64: PMU: Avoid inappropriate use of host's PMUVer commit: 335ca49ff31f145c0f08540614062197a334e064 [3/4] KVM: arm64: PMU: Don't advertise the STALL_SLOT event commit: 8c694f557fd80ca9815ddb1cf5de10d8bf168110 [4/4] KVM: arm64: PMU: Don't advertise STALL_SLOT_{FRONTEND,BACKEND} commit: 64b81000b60b70f10a5834023fe100902d9f7a57 Cheers, M.
This series fixes a couple of PMUver related handling of vPMU support. On systems where the PMUVer is not uniform across all PEs, KVM currently does not advertise PMUv3 to the guest, even if userspace successfully runs KVM_ARM_VCPU_INIT with KVM_ARM_VCPU_PMU_V3. The patch-1 will address this inconsistent behavior by disallowing userspace from configuring vPMU, as such systems would be extremely uncommon and unlikely to even use KVM (according to Marc [1]). The patch-2 will fix improper use of the host's PMUver to determine a valid range of PMU events for the guest (the guest's PMUver should be used instead). The patch-3 and patch-4 will try to hide the STALL_SLOT* events unconditionally per Oliver's suggestion [2]. Presently, KVM hides the STALL_SLOT event depending on the host PMU version, instead of the guest's PMU version, which doesn't seem to be accurate, as it appears that older PMU than PMUv3p4 could implement the event according to the Arm ARM. Exposing the STALL_SLOT event without PMMIR_EL1 (supported from PMUv3p4) for the guest won't be very useful though. The patch-3 stops advertising the event for guest unconditionally, rather than fixing or keeping the inaccurate checking to advertise the event for the case, where it is not very useful. The patch-4 stops advertising the STALL_SLOT_{FRONT,BACK}END events to the guest, similar to the STALL_SLOT event, as when any of these three events are implemented, all three of them should be implemented, according to the Arm ARM. This series is based on 6.5-rc6. v3: - Fixed to not insert the host PMU instance in the list of valid PMUs [Oliver] v2: https://lore.kernel.org/all/20230728181907.1759513-1-reijiw@google.com/ - Combined a two separate v1 series - Disallow STALL_SLOT* event unconditionally [Oliver] v1: https://lore.kernel.org/all/20230610061520.3026530-1-reijiw@google.com/ https://lore.kernel.org/all/20230610194510.4146549-1-reijiw@google.com/ [1] https://lore.kernel.org/all/874jnqp73o.wl-maz@kernel.org/ [2] https://lore.kernel.org/all/ZIm1kdFBfXYMdfbV@linux.dev/ Reiji Watanabe (4): KVM: arm64: PMU: Disallow vPMU on non-uniform PMUVer KVM: arm64: PMU: Avoid inappropriate use of host's PMUVer KVM: arm64: PMU: Don't advertise the STALL_SLOT event KVM: arm64: PMU: Don't advertise STALL_SLOT_{FRONTEND,BACKEND} arch/arm64/kvm/pmu-emul.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) base-commit: 2ccdd1b13c591d306f0401d98dedc4bdcd02b421