[GIT PULL] KVM: Generic changes for 6.13

[Sean Christopherson]

Please pull two changes that coincidentally happen to be related to vcpu->pid.

The following changes since commit 5cb1659f412041e4780f2e8ee49b2e03728a2ba6:

  Merge branch 'kvm-no-struct-page' into HEAD (2024-10-25 13:38:16 -0400)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-generic-6.13

for you to fetch changes up to 3e7f43188ee227bcf0f07f60a00f1fd1aca10e6a:

  KVM: Protect vCPU's "last run PID" with rwlock, not RCU (2024-10-30 14:41:22 -0700)

----------------------------------------------------------------
KVM generic changes for 6.13

 - Rework kvm_vcpu_on_spin() to use a single for-loop instead of making two
   partial poasses over "all" vCPUs.  Opportunistically expand the comment
   to better explain the motivation and logic.

 - Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock instead
   of RCU, so that running a vCPU on a different task doesn't encounter
   long stalls due to having to wait for all CPUs become quiescent.

----------------------------------------------------------------
Sean Christopherson (3):
      KVM: Rework core loop of kvm_vcpu_on_spin() to use a single for-loop
      KVM: Return '0' directly when there's no task to yield to
      KVM: Protect vCPU's "last run PID" with rwlock, not RCU

 arch/arm64/include/asm/kvm_host.h |   2 +-
 include/linux/kvm_host.h          |   3 +-
 virt/kvm/kvm_main.c               | 143 ++++++++++++++++++++++----------------
 3 files changed, 86 insertions(+), 62 deletions(-)