Hi David, On 2/29/24 05:57, David Stevens wrote: > From: David Stevens <stevensd@xxxxxxxxxxxx> > > Handle non-refcounted pages in __kvm_faultin_pfn. This allows the > host to map memory into the guest that is backed by non-refcounted > struct pages - for example, the tail pages of higher order non-compound > pages allocated by the amdgpu driver via ttm_pool_alloc_page. > > Signed-off-by: David Stevens <stevensd@xxxxxxxxxxxx> This patch has a problem on v6.8 kernel. Pierre-Eric of AMD found that Qemu crashes with "kvm bad address" error when booting Ubuntu 23.10 ISO with a disabled virtio-gpu and I was able to reproduce it. Pierre-Eric said this problem didn't exist with v6.7 kernel and using v10 kvm patches. Could you please take a look at this issue? To reproduce the bug, run Qemu like this and load the Ubuntu installer: qemu-system-x86_64 -boot d -cdrom ubuntu-23.10.1-desktop-amd64.iso -m 4G --enable-kvm -display gtk -smp 1 -machine q35 Qemu fails with "error: kvm run failed Bad address" On the host kernel there is this warning: ------------[ cut here ]------------ WARNING: CPU: 19 PID: 11696 at mm/gup.c:229 try_grab_page+0x64/0x100 Call Trace: <TASK> ? try_grab_page+0x64/0x100 ? __warn+0x81/0x130 ? try_grab_page+0x64/0x100 ? report_bug+0x171/0x1a0 ? handle_bug+0x3c/0x80 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? try_grab_page+0x64/0x100 follow_page_pte+0xfa/0x4b0 __get_user_pages+0xe5/0x6e0 get_user_pages_unlocked+0xe7/0x370 hva_to_pfn+0xa2/0x760 [kvm] ? free_unref_page+0xf9/0x180 kvm_faultin_pfn+0x112/0x610 [kvm] kvm_tdp_page_fault+0x104/0x150 [kvm] kvm_mmu_page_fault+0x298/0x860 [kvm] kvm_arch_vcpu_ioctl_run+0xc7d/0x16b0 [kvm] ? srso_alias_return_thunk+0x5/0xfbef5 ? kvm_arch_vcpu_put+0x128/0x190 [kvm] ? srso_alias_return_thunk+0x5/0xfbef5 kvm_vcpu_ioctl+0x199/0x700 [kvm] __x64_sys_ioctl+0x94/0xd0 do_syscall_64+0x86/0x170 ? kvm_on_user_return+0x64/0x90 [kvm] ? srso_alias_return_thunk+0x5/0xfbef5 ? fire_user_return_notifiers+0x37/0x70 ? srso_alias_return_thunk+0x5/0xfbef5 ? syscall_exit_to_user_mode+0x80/0x230 ? srso_alias_return_thunk+0x5/0xfbef5 ? do_syscall_64+0x96/0x170 ? srso_alias_return_thunk+0x5/0xfbef5 ? do_syscall_64+0x96/0x170 ? do_syscall_64+0x96/0x170 ? do_syscall_64+0x96/0x170 ? srso_alias_return_thunk+0x5/0xfbef5 ? do_syscall_64+0x96/0x170 ? srso_alias_return_thunk+0x5/0xfbef5 entry_SYSCALL_64_after_hwframe+0x6e/0x76 ---[ end trace 0000000000000000 ]--- -- Best regards, Dmitry
