[GIT PULL] KVM: Common changes for 6.12

From: Sean Christopherson
Date: Fri Sep 13 2024 - 21:14:14 EST


Fix a long-standing goof in the coalesced IO code, and a lurking bug in
kvm_clear_guest().

The following changes since commit 47ac09b91befbb6a235ab620c32af719f8208399:

Linux 6.11-rc4 (2024-08-18 13:17:27 -0700)

are available in the Git repository at:

https://github.com/kvm-x86/linux.git tags/kvm-x86-generic-6.12

for you to fetch changes up to 025dde582bbf31e7618f9283594ef5e2408e384b:

KVM: Harden guest memory APIs against out-of-bounds accesses (2024-09-09 20:15:34 -0700)

----------------------------------------------------------------
KVK generic changes for 6.12:

- Fix a bug that results in KVM prematurely exiting to userspace for coalesced
MMIO/PIO in many cases, clean up the related code, and add a testcase.

- Fix a bug in kvm_clear_guest() where it would trigger a buffer overflow _if_
the gpa+len crosses a page boundary, which thankfully is guaranteed to not
happen in the current code base. Add WARNs in more helpers that read/write
guest memory to detect similar bugs.

----------------------------------------------------------------
Ilias Stamatis (1):
KVM: Fix coalesced_mmio_has_room() to avoid premature userspace exit

Sean Christopherson (4):
KVM: selftests: Add a test for coalesced MMIO (and PIO on x86)
KVM: Clean up coalesced MMIO ring full check
KVM: Write the per-page "segment" when clearing (part of) a guest page
KVM: Harden guest memory APIs against out-of-bounds accesses

tools/testing/selftests/kvm/Makefile | 3 +
tools/testing/selftests/kvm/coalesced_io_test.c | 236 ++++++++++++++++++++++++
tools/testing/selftests/kvm/include/kvm_util.h | 26 +++
virt/kvm/coalesced_mmio.c | 31 +---
virt/kvm/kvm_main.c | 11 +-
5 files changed, 283 insertions(+), 24 deletions(-)
create mode 100644 tools/testing/selftests/kvm/coalesced_io_test.c