| Message ID | 20240621224044.2465901-1-oliver.upton@linux.dev (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: nv: Unfudge ID_AA64PFR0_EL1 masking | expand |
On Fri, 21 Jun 2024 23:40:44 +0100, Oliver Upton <oliver.upton@linux.dev> wrote: > > Marc reports that L1 VMs aren't booting with the NV series applied to > today's kvmarm/next. After bisecting the issue, it appears that > 44241f34fac9 ("KVM: arm64: nv: Use accessors for modifying ID > registers") is to blame. > > Poking around at the issue a bit further, it'd appear that the value for > ID_AA64PFR0_EL1 is complete garbage, as 'val' still contains the value > we set ID_AA64ISAR1_EL1 to. > > Fix the read-modify-write pattern to actually use ID_AA64PFR0_EL1 as the > starting point. Excuse me as I return to my shame cube. > > Reported-by: Marc Zyngier <maz@kernel.org> > Fixes: 44241f34fac9 ("KVM: arm64: nv: Use accessors for modifying ID registers") > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Confirmed, we're back in business. Acked-by: Marc Zyngier <maz@kernel.org> Tested-by: Marc Zyngier <maz@kernel.org> Thanks, M.
On Fri, 21 Jun 2024 22:40:44 +0000, Oliver Upton wrote: > Marc reports that L1 VMs aren't booting with the NV series applied to > today's kvmarm/next. After bisecting the issue, it appears that > 44241f34fac9 ("KVM: arm64: nv: Use accessors for modifying ID > registers") is to blame. > > Poking around at the issue a bit further, it'd appear that the value for > ID_AA64PFR0_EL1 is complete garbage, as 'val' still contains the value > we set ID_AA64ISAR1_EL1 to. > > [...] Applied to kvmarm/next, thanks! [1/1] KVM: arm64: nv: Unfudge ID_AA64PFR0_EL1 masking https://git.kernel.org/kvmarm/kvmarm/c/33d85a93c6c3 -- Best, Oliver
diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index f02089d98445..96029a95d106 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -815,7 +815,7 @@ static void limit_nv_id_regs(struct kvm *kvm) kvm_set_vm_id_reg(kvm, SYS_ID_AA64ISAR1_EL1, val); /* No AMU, MPAM, S-EL2, or RAS */ - kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1); + val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1); val &= ~(GENMASK_ULL(55, 52) | NV_FTR(PFR0, AMU) | NV_FTR(PFR0, MPAM) |
Marc reports that L1 VMs aren't booting with the NV series applied to today's kvmarm/next. After bisecting the issue, it appears that 44241f34fac9 ("KVM: arm64: nv: Use accessors for modifying ID registers") is to blame. Poking around at the issue a bit further, it'd appear that the value for ID_AA64PFR0_EL1 is complete garbage, as 'val' still contains the value we set ID_AA64ISAR1_EL1 to. Fix the read-modify-write pattern to actually use ID_AA64PFR0_EL1 as the starting point. Excuse me as I return to my shame cube. Reported-by: Marc Zyngier <maz@kernel.org> Fixes: 44241f34fac9 ("KVM: arm64: nv: Use accessors for modifying ID registers") Signed-off-by: Oliver Upton <oliver.upton@linux.dev> --- arch/arm64/kvm/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) base-commit: a9e3d7734719d5b58f260edc15dce3ea4dc3d313