On 31 May 2018 at 20:57, Greg Kurz <gr...@kaod.org> wrote: > On Thu, 31 May 2018 09:38:10 +0200 > Cédric Le Goater <c...@kaod.org> wrote: > >> On 05/30/2018 04:42 PM, Joel Stanley wrote: >> > The powerpc Linux kernel[1] and skiboot firmware[2] recently gained changes >> > that cause the Processor Compatibility Register (PCR) SPR to be cleared. >> > >> > These changes cause Linux to fail to boot on the Qemu powernv machine >> > with an error: >> > >> > Trying to write privileged spr 338 (0x152) at 0000000030017f0c >> > >> > With this patch Qemu makes this register available as a hypervisor >> > privileged register. >> > >> > Note that bits set in this register disable features of the processor. >> > Currently the only register state that is supported is when the register >> > is zeroed (enable all features). This is sufficient for guests to >> > once again boot. >> > >> > [1] https://lkml.kernel.org/r/20180518013742.24095-1-mi...@neuling.org >> > [2] https://patchwork.ozlabs.org/patch/915932/ >> > >> > Signed-off-by: Joel Stanley <j...@jms.id.au> >> > --- >> > target/ppc/helper.h | 1 + >> > target/ppc/misc_helper.c | 10 ++++++++++ >> > target/ppc/translate_init.inc.c | 9 +++++++-- >> > 3 files changed, 18 insertions(+), 2 deletions(-) >> > >> > diff --git a/target/ppc/helper.h b/target/ppc/helper.h >> > index 19453c68138a..d751f0e21909 100644 >> > --- a/target/ppc/helper.h >> > +++ b/target/ppc/helper.h >> > @@ -17,6 +17,7 @@ DEF_HELPER_2(pminsn, void, env, i32) >> > DEF_HELPER_1(rfid, void, env) >> > DEF_HELPER_1(hrfid, void, env) >> > DEF_HELPER_2(store_lpcr, void, env, tl) >> > +DEF_HELPER_2(store_pcr, void, env, tl) >> > #endif >> > DEF_HELPER_1(check_tlb_flush_local, void, env) >> > DEF_HELPER_1(check_tlb_flush_global, void, env) >> > diff --git a/target/ppc/misc_helper.c b/target/ppc/misc_helper.c >> > index 8c8cba5cc6f1..40c39d08ad14 100644 >> > --- a/target/ppc/misc_helper.c >> > +++ b/target/ppc/misc_helper.c >> > @@ -20,6 +20,7 @@ >> > #include "cpu.h" >> > #include "exec/exec-all.h" >> > #include "exec/helper-proto.h" >> > +#include "qemu/error-report.h" >> > >> > #include "helper_regs.h" >> > >> > @@ -186,6 +187,15 @@ void ppc_store_msr(CPUPPCState *env, target_ulong >> > value) >> > hreg_store_msr(env, value, 0); >> > } >> > >> > +void helper_store_pcr(CPUPPCState *env, target_ulong value) >> > +{ >> > + if (value != 0) { >> > + error_report("Unimplemented PCR value 0x"TARGET_FMT_lx, value); >> > + return; >> > + } >> > + env->spr[SPR_PCR] = value; >> >> shouldn't we use pcc->pcr_mask ? and check pcc->pcr_supported also ? >> > > pcc->pcr_mask and ppc->pcr_supported only make sense for pseries machine > types (ie, when the spapr machine code call ppc_*_compat() functions). > > The case here is different: we're running a fully emulated pnv machine, > ie, PCR can only be set by mtspr() called within the pnv guest. But TCG > doesn't implement the compatibility mode logic, ie, the CPU always run > in "raw" mode, ie, we only support PCR == 0, actually.
Okay, thanks for clarifying. Cedric suggested offline that I could change "Unimplemented..." to "Invalid...". Are there any other changes you would like? > So, this patch looks good for me. I'm just not sure about what is > causing the build break with patchew though... I can't reproduce the failure here either. Cheers, Joel
