Hi Vaibhav, Thanks for reviewing the patch. Please find my response below.
On 2026/06/19 04:45 PM, Vaibhav Jain wrote: > Hi Amit, > > Thanks for the patch. My review comments inline below: > > Amit Machhiwal <[email protected]> writes: > > > On POWER systems, the host CPU may run in a compatibility mode (e.g., > > a Power11 processor operating in Power10 compatibility mode). When > > running nested KVM guests, QEMU currently derives the host CPU type > > using mfpvr(), which reflects the physical processor version. This can > > result in a mismatch between the CPU model used by QEMU and the > > compatibility mode enforced by the host, leading to guest boot failures > > such as "KVM-NESTEDv2: couldn't set guest wide elements". > > > > Update kvm_ppc_get_host_cpu_class() to check if the host is running in > > a compatibility mode using kvm_ppc_host_compat_pvr(). When available, > > use the compatibility PVR instead of the raw hardware PVR when selecting > > the CPU model. This ensures that QEMU selects a CPU model consistent > > with the host compatibility mode, allowing nested guests to boot > > correctly. > > > > Signed-off-by: Amit Machhiwal <[email protected]> > > --- > > target/ppc/kvm.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c > > index 9e5006e0c2cd..a72f237f0c8a 100644 > > --- a/target/ppc/kvm.c > > +++ b/target/ppc/kvm.c > > @@ -2672,6 +2672,15 @@ PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void) > > uint32_t host_pvr = mfpvr(); > > PowerPCCPUClass *pvr_pcc; > > > > +#if defined(TARGET_PPC64) > Use CONFIG_KVM As I mentioned in the response to previous patch's review comments, the TARGET_PPC64 guard is needed to fix ppc32 build breakage, and CONFIG_KVM would be redundant since target/ppc/kvm.c is only compiled when CONFIG_KVM=y. Thanks, Amit > > > + uint32_t compat_host_pvr; > > + > > + compat_host_pvr = kvm_ppc_host_compat_pvr(); > > + if (compat_host_pvr) { > > + host_pvr = compat_host_pvr; > > + } > > +#endif /* TARGET_PPC64 */ > > + > > pvr_pcc = ppc_cpu_class_by_pvr(host_pvr); > > if (pvr_pcc == NULL) { > > pvr_pcc = ppc_cpu_class_by_pvr_mask(host_pvr); > > -- > > 2.50.1 (Apple Git-155) > > > > > > -- > Cheers > ~ Vaibhav
