On Thu, Jun 01, 2017 at 09:29:08AM +0200, Greg Kurz wrote: > On Thu, 01 Jun 2017 15:44:40 +1000 > Suraj Jitindar Singh <sjitindarsi...@gmail.com> wrote: > > > On Fri, 2017-05-26 at 15:23 +1000, David Gibson wrote: > > > Server class POWER CPUs have a "compat" property, which is used to > > > set the > > > backwards compatibility mode for the processor. However, this only > > > makes > > > sense for machine types which don't give the guest access to > > > hypervisor > > > privilege - otherwise the compatibility level is under the guest's > > > control. > > > > > > To reflect this, this removes the CPU 'compat' property and instead > > > creates a 'max-cpu-compat' property on the pseries machine. Strictly > > > speaking this breaks compatibility, but AFAIK the 'compat' option was > > > never (directly) used with -device or device_add. > > > > > > The option was used with -cpu. So, to maintain compatibility, this > > > patch adds a hack to the cpu option parsing to strip out any compat > > > options supplied with -cpu and set them on the machine property > > > instead of the now deprecated cpu property. > > > > Generally looks good, a couple of comments below. > > > > Suraj > > > > > > > > Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> > > > --- > > > hw/ppc/spapr.c | 6 ++- > > > hw/ppc/spapr_cpu_core.c | 56 +++++++++++++++++++++++- > > > hw/ppc/spapr_hcall.c | 8 ++-- > > > include/hw/ppc/spapr.h | 12 ++++-- > > > target/ppc/compat.c | 102 > > > ++++++++++++++++++++++++++++++++++++++++++++ > > > target/ppc/cpu.h | 5 ++- > > > target/ppc/translate_init.c | 86 +++++++++++----------------------- > > > --- > > > 7 files changed, 202 insertions(+), 73 deletions(-) > > > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > > > index ab3aab1..3c4e88f 100644 > > > --- a/hw/ppc/spapr.c > > > +++ b/hw/ppc/spapr.c > > > @@ -2134,7 +2134,7 @@ static void ppc_spapr_init(MachineState > > > *machine) > > > machine->cpu_model = kvm_enabled() ? "host" : smc- > > > >tcg_default_cpu; > > > } > > > > > > - ppc_cpu_parse_features(machine->cpu_model); > > > + spapr_cpu_parse_features(spapr); > > > > > > spapr_init_cpus(spapr); > > > > > > @@ -2497,6 +2497,10 @@ static void spapr_machine_initfn(Object *obj) > > > " place of standard EPOW events > > > when possible" > > > " (required for memory hot- > > > unplug support)", > > > NULL); > > > + > > > + ppc_compat_add_property(obj, "max-cpu-compat", &spapr- > > > >max_compat_pvr, > > > + "Maximum permitted CPU compatibility > > > mode", > > > + &error_fatal); > > > } > > > > > > static void spapr_machine_finalizefn(Object *obj) > > > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c > > > index ff7058e..ab4102b 100644 > > > --- a/hw/ppc/spapr_cpu_core.c > > > +++ b/hw/ppc/spapr_cpu_core.c > > > @@ -20,6 +20,58 @@ > > > #include "sysemu/numa.h" > > > #include "qemu/error-report.h" > > > > > > +void spapr_cpu_parse_features(sPAPRMachineState *spapr) > > > +{ > > > + /* > > > + * Backwards compatibility hack: > > > + * > > > + * CPUs had a "compat=" property which didn't make sense for > > > + * anything except pseries. It was replaced by "max-cpu- > > > compat" > > > + * machine option. This supports old command lines like > > > + * -cpu POWER8,compat=power7 > > > + * By stripping the compat option and applying it to the > > > machine > > > + * before passing it on to the cpu level parser. > > > + */ > > > + gchar **inpieces; > > > + int i, j; > > > + gchar *compat_str = NULL; > > > + > > > + inpieces = g_strsplit(MACHINE(spapr)->cpu_model, ",", 0); > > > + > > > + /* inpieces[0] is the actual model string */ > > > + i = 1; > > > + j = 1; > > > + while (inpieces[i]) { > > > + if (g_str_has_prefix(inpieces[i], "compat=")) { > > > + /* in case of multiple compat= optipons */ > > > > s/optipons/options? > > > > > + g_free(compat_str); > > > + compat_str = inpieces[i]; > > > + } else { > > > + j++; > > > + } > > > + > > > + /* Excise compat options from list */ > > > + inpieces[j] = inpieces[i]; > > > > it's worth noting that where previously when specifying an invalid > > option you got: > > > > qemu-system-ppc64: Expected key=value format, found *blah* > > > > You now get a segfault here. > > > > Yeah. This basically does: > > inpieces[i + 1] = inpieces[i]; > > and we end up overwriting the terminal NULL pointer with a non-NULL > pointer. > > What about simplifying the loop to: > > /* inpieces[0] is the actual model string */ > i = 1; > while (inpieces[i]) { > if (g_str_has_prefix(inpieces[i], "compat=")) { > /* in case of multiple compat= optipons */ > g_free(compat_str); > compat_str = inpieces[i]; > /* Excise compat options from list */ > inpieces[i] = inpieces[i + 1]; > } > i++; > }
No.. that would duplicate the entry after the compat=, instead of properly excising it. I've already fixed this for my next draft. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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