[GIT,PULL] KVM: vcpu_array fixes and cleanups for 6.14

Pull-request

https://github.com/kvm-x86/linux.git tags/kvm-x86-vcpu_array-6.14

Message

Sean Christopherson Jan. 17, 2025, 1:07 a.m. UTC

The wonderful vcpu_array changes that you already know and love :-D

The following changes since commit 3522c419758ee8dca5a0e8753ee0070a22157bc1:

  Merge tag 'kvm-riscv-fixes-6.13-1' of https://github.com/kvm-riscv/linux into HEAD (2024-12-13 13:59:20 -0500)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-vcpu_array-6.14

for you to fetch changes up to 01528db67f28d5919f7b0a68900dc212165218e2:

  KVM: Drop hack that "manually" informs lockdep of kvm->lock vs. vcpu->mutex (2024-12-16 14:37:30 -0800)

----------------------------------------------------------------
KVM vcpu_array fixes and cleanups for 6.14:

 - Explicitly verify the target vCPU is online in kvm_get_vcpu() to fix a bug
   where KVM would return a pointer to a vCPU prior to it being fully online,
   and give kvm_for_each_vcpu() similar treatment to fix a similar flaw.

 - Wait for a vCPU to come online prior to executing a vCPU ioctl to fix a
   bug where userspace could coerce KVM into handling the ioctl on a vCPU that
   isn't yet onlined.

 - Gracefully handle xa_insert() failures even though such failuires should be
   impossible in practice.

----------------------------------------------------------------
Sean Christopherson (6):
      KVM: Explicitly verify target vCPU is online in kvm_get_vcpu()
      KVM: Verify there's at least one online vCPU when iterating over all vCPUs
      KVM: Grab vcpu->mutex across installing the vCPU's fd and bumping online_vcpus
      Revert "KVM: Fix vcpu_array[0] races"
      KVM: Don't BUG() the kernel if xa_insert() fails with -EBUSY
      KVM: Drop hack that "manually" informs lockdep of kvm->lock vs. vcpu->mutex

 include/linux/kvm_host.h | 16 +++++++++---
 virt/kvm/kvm_main.c      | 68 ++++++++++++++++++++++++++++++++++++------------
 2 files changed, 65 insertions(+), 19 deletions(-)