On Fri, 06 Sep 2024 18:18:20 -0400, Maxim Levitsky wrote: > Recently we came up upon a failure where likely the guest writes > 0xff4547ceb1600000 to MSR_KERNEL_GS_BASE and later on, qemu > sets this value via KVM_PUT_MSRS, and is rejected by the > kernel, likely due to not being canonical in 4 level paging. > > One of the way to trigger this is to make the guest enter SMM, > which causes paging to be disabled, which SMM bios re-enables > but not the whole 5 level. MSR_KERNEL_GS_BASE on the other > hand continues to contain old value. > > [...] Applied to kvm-x86 misc, with some massaging (see responsed to individual patches). Thanks! [1/4] KVM: x86: drop x86.h include from cpuid.h https://github.com/kvm-x86/linux/commit/391bd0c520c1 [2/4] KVM: x86: implement emul_is_noncanonical_address using is_noncanonical_address https://github.com/kvm-x86/linux/commit/6c45d62536d0 [3/4] KVM: x86: model canonical checks more precisely https://github.com/kvm-x86/linux/commit/1b1336d1d858 [4/4] KVM: nVMX: fix canonical check of vmcs12 HOST_RIP https://github.com/kvm-x86/linux/commit/14a95598b6e7 -- https://github.com/kvm-x86/linux/tree/next