On Wed, Sep 23, 2026 at 12:18:10PM +0100, Fuad Tabba wrote: > Hi Lorenzo, > > On Tue, 22 Sep 2026 15:18:04 +0100, "Lorenzo Stoakes (ARM)" > <[email protected]> wrote: > [...] > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > [...] > > +static long __pre_fault_s2(struct kvm_s2_mmu *mmu, struct kvm_vcpu *vcpu, > > + gpa_t gpa, struct kvm_memory_slot *memslot, s8 > > level) > [...] > > + if (is_gmem) > > + ret = gmem_abort(&s2fd, &result); > > + else > > + ret = user_mem_abort(&s2fd, &result); > > When kvm_gmem_get_pfn() fails, gmem_abort() calls > kvm_prepare_memory_fault_exit() before returning, which on this path > writes vcpu->run's exit_reason and memory_fault fields outside > KVM_RUN. If that happens on a vCPU between its KVM_EXIT_MMIO and its > next KVM_RUN, kvm_arch_vcpu_ioctl_run() reads KVM_EXIT_MEMORY_FAULT > instead, skips kvm_handle_mmio_return(), and the guest repeats the > access. Could gmem_abort() skip that exit when result is set? > user_mem_abort() never writes kvm_run.
Ack yeah we shouldn't be updating vcpu->run like that in that case, will update to avoid doing that in v4. > > Cheers, > /fuad -- Cheers, Lorenzo
