We're currently getting a Program Interrupt inside the nested guest kernel when running with GTSE disabled in the nested hypervisor. We allow any guest a cmdline override of GTSE for migration purposes. The nested guest does not know it needs to use the option and tries to run 'tlbie' with LPCR_GTSE=0. The details are a bit more intricate: QEMU always sets GTSE=1 in OV5 even before calling KVM. At prom_init, guests use the OV5 value to set MMU_FTR_GTSE. This setting can be overridden by 'radix_hcall_invalidate=on' in the kernel cmdline. The option itself depends on the availability of FW_FEATURE_RPT_INVALIDATE, which it tied to QEMU's cap-rpt-invalidate capability. The MMU_FTR_GTSE flag leads guests to set PROC_TABLE_GTSE in their process tables and after H_REGISTER_PROC_TBL, both QEMU and KVM will set LPCR_GTSE=1 for that guest. Unless the guest uses the cmdline override, in which case: MMU_FTR_GTSE=0 -> PROC_TABLE_GTSE=0 -> LPCR_GTSE=0 We don't allow the nested hypervisor to set some LPCR bits for its nested guests, so if the nested HV has LPCR_GTSE=0, its nested guests will also have LPCR_GTSE=0. But since the only thing that can really flip GTSE is the cmdline override, if a nested guest runs without it, then the sequence goes: MMU_FTR_GTSE=1 -> PROC_TABLE_GTSE=1 -> LPCR_GTSE=0. With LPCR_GTSE=0 the HW will treat 'tlbie' as HV privileged. This patch allows a nested HV to set LPCR_GTSE for its nested guests so the LPCR setting will match what the nested guest sees in OV5. Signed-off-by: Fabiano Rosas <farosas@xxxxxxxxxxxxx> --- arch/powerpc/kvm/book3s_hv_nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c index 9d373f8963ee..5b9008d89f90 100644 --- a/arch/powerpc/kvm/book3s_hv_nested.c +++ b/arch/powerpc/kvm/book3s_hv_nested.c @@ -262,7 +262,7 @@ static void load_l2_hv_regs(struct kvm_vcpu *vcpu, * Don't let L1 change LPCR bits for the L2 except these: */ mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD | - LPCR_LPES | LPCR_MER; + LPCR_LPES | LPCR_MER | LPCR_GTSE; /* * Additional filtering is required depending on hardware -- 2.34.1
