mbox series

[v2,0/3] KVM: arm64: PMU: Fix SET_ONE_REG for vPMC regs

Message ID 20250307-pmc-v2-0-6c3375a5f1e4@daynix.com (mailing list archive)
Headers show
Series KVM: arm64: PMU: Fix SET_ONE_REG for vPMC regs | expand

Message

Akihiko Odaki March 7, 2025, 10:55 a.m. UTC 
Prepare vPMC registers for user-initiated changes after first run. This
is important specifically for debugging Windows on QEMU with GDB; QEMU
tries to write back all visible registers when resuming the VM execution
with GDB, corrupting the PMU state. Windows always uses the PMU so this
can cause adverse effects on that particular OS.

This series also contains patch "KVM: arm64: PMU: Set raw values from
user to PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}", which reverts semantic
changes made for the mentioned registers in the past. It is necessary
to migrate the PMU state properly on Firecracker, QEMU, and crosvm.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
Changes in v2:
- Changed to utilize KVM_REQ_RELOAD_PMU as suggested by Oliver Upton.
- Added patch "KVM: arm64: PMU: Reload when user modifies registers"
  to cover more registers.
- Added patch "KVM: arm64: PMU: Set raw values from user to
  PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}".
- Link to v1: https://lore.kernel.org/r/20250302-pmc-v1-1-caff989093dc@daynix.com

---
Akihiko Odaki (3):
      KVM: arm64: PMU: Fix SET_ONE_REG for vPMC regs
      KVM: arm64: PMU: Reload when user modifies registers
      KVM: arm64: PMU: Set raw values from user to PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}

 arch/arm64/kvm/pmu-emul.c | 19 ++++++++++++++++---
 arch/arm64/kvm/sys_regs.c | 44 ++++++++++++++++++++++++--------------------
 include/kvm/arm_pmu.h     |  1 +
 3 files changed, 41 insertions(+), 23 deletions(-)
---
base-commit: da2f480cb24d39d480b1e235eda0dd2d01f8765b
change-id: 20250302-pmc-b90a86af945c

Best regards,