The highlights are two fixes for bugs where "destroying" and "initializing" a gfn=>pfn cache while it is being accessed results in various forms of badness, e.g. re-initialization of an in-use lock, consuming a NULL pointer, potential memory corruption, etc... Everything else is cleanup to make the gpc APIs easier to use and harder to use incorrectly. David, patch 3 (KVM: x86: Always use non-compat vcpu_runstate_info size...) in particular needs your eyeballs. I'm pretty sure it's ok, but confirmation from someone that actually uses KVM XEN would be nice. v2: - Fix active vs. valid race by rejecting refresh() if the cache is currently invalid. - Tweak shortlogs to be "KVM" only. Even though x86 is the only user of the caches, I think it makes sense to tag the changes as "full" KVM for future readers. - Add back the selftest (from the RFC) that triggers the race conditions. - Always use non-compat size for checking+refreshing runstate_info and make @len truly immutable. - Drop unmap() for the moment. I started adding code to prevent "bad" usage, but without any user I couldn't figure out exactly what restrictions need to be in place. - Do more cleanup. v1: https://lore.kernel.org/all/20220921020140.3240092-1-mhal@xxxxxxx Michal Luczaj (9): KVM: Initialize gfn_to_pfn_cache locks in dedicated helper KVM: Shorten gfn_to_pfn_cache function names KVM: x86: Remove unused argument in gpc_unmap_khva() KVM: Store immutable gfn_to_pfn_cache properties KVM: Store gfn_to_pfn_cache length as an immutable property KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_check() KVM: Clean up hva_to_pfn_retry() KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_refresh() KVM: selftests: Add tests in xen_shinfo_test to detect lock races Sean Christopherson (7): KVM: Reject attempts to consume or refresh inactive gfn_to_pfn_cache KVM: x86: Always use non-compat vcpu_runstate_info size for gfn=>pfn cache KVM: Drop KVM's API to allow temprorarily unmapping gfn=>pfn cache KVM: Do not partially reinitialize gfn=>pfn cache during activation KVM: Drop @gpa from exported gfn=>pfn cache check() and refresh() helpers KVM: Skip unnecessary "unmap" if gpc is already valid during refresh KVM: selftests: Mark "guest_saw_irq" as volatile in xen_shinfo_test arch/x86/kvm/x86.c | 24 +-- arch/x86/kvm/xen.c | 84 ++++----- include/linux/kvm_host.h | 73 ++++---- include/linux/kvm_types.h | 2 + .../selftests/kvm/x86_64/xen_shinfo_test.c | 142 ++++++++++++++- virt/kvm/pfncache.c | 170 ++++++++++-------- 6 files changed, 320 insertions(+), 175 deletions(-) base-commit: e18d6152ff0f41b7f01f9817372022df04e0d354 -- 2.38.0.413.g74048e4d9e-goog
