mirror of https://github.com/proxmox/mirror_qemu
ppc: fix setting of compat mode
While trying to make KVM PR usable again, commit 5dfaa532ae introduced a regression: the current compat_pvr value is passed to KVM instead of the new one. This means that we always pass 0 instead of the max-cpu-compat PVR during the initial machine reset. And at CAS time, we either pass the PVR from the command line or even don't call kvmppc_set_compat() at all, ie, the PCR will not be set as expected. For example if we start a big endian fedora26 guest in power7 compat mode on a POWER8 host, we get this in the guest: $ cat /proc/cpuinfo processor : 0 cpu : POWER7 (architected), altivec supported clock : 4024.000000MHz revision : 2.0 (pvr 004d 0200) timebase : 512000000 platform : pSeries model : IBM pSeries (emulated by qemu) machine : CHRP IBM pSeries (emulated by qemu) MMU : Hash but the guest can still execute POWER8 instructions, and the following program succeeds: int main() { asm("vncipher 0,0,0"); // ISA 2.07 instruction } Let's pass the new compat_pvr to kvmppc_set_compat() and the program fails with SIGILL as expected. Reported-by: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com> Signed-off-by: Greg Kurz <groug@kaod.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>master
parent
b0fbe46ad8
commit
e4f0c6bb1a
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@ -141,7 +141,7 @@ void ppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr, Error **errp)
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cpu_synchronize_state(CPU(cpu));
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if (kvm_enabled() && cpu->compat_pvr != compat_pvr) {
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int ret = kvmppc_set_compat(cpu, cpu->compat_pvr);
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int ret = kvmppc_set_compat(cpu, compat_pvr);
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if (ret < 0) {
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error_setg_errno(errp, -ret,
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"Unable to set CPU compatibility mode in KVM");
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