On Mon, Jun 04, 2018 at 06:15:13PM +0930, 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>
Applied to ppc-for-3.0, thanks.
> ---
> v2:
> - Change error message to say Invalid instead of Unimplemented
> - Fix compile warning on other powerpc targets, thanks patchew
> v3:
> - Mask against pcr_mask before storing
> - Drop check for non-zero value
> ---
> target/ppc/helper.h | 1 +
> target/ppc/misc_helper.c | 9 +++++++++
> target/ppc/translate_init.inc.c | 9 +++++++--
> 3 files changed, 17 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..b88493009609 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"
>
> @@ -98,6 +99,14 @@ void helper_store_ptcr(CPUPPCState *env, target_ulong val)
> tlb_flush(CPU(cpu));
> }
> }
> +
> +void helper_store_pcr(CPUPPCState *env, target_ulong value)
> +{
> + PowerPCCPU *cpu = ppc_env_get_cpu(env);
> + PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
> +
> + env->spr[SPR_PCR] = value & pcc->pcr_mask;
> +}
> #endif /* defined(TARGET_PPC64) */
>
> void helper_store_pidr(CPUPPCState *env, target_ulong val)
> diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c
> index ab782cb32aaa..1a89017ddea8 100644
> --- a/target/ppc/translate_init.inc.c
> +++ b/target/ppc/translate_init.inc.c
> @@ -424,6 +424,10 @@ static void spr_write_ptcr(DisasContext *ctx, int sprn,
> int gprn)
> gen_helper_store_ptcr(cpu_env, cpu_gpr[gprn]);
> }
>
> +static void spr_write_pcr(DisasContext *ctx, int sprn, int gprn)
> +{
> + gen_helper_store_pcr(cpu_env, cpu_gpr[gprn]);
> +}
> #endif
> #endif
>
> @@ -7957,11 +7961,12 @@ static void gen_spr_power6_common(CPUPPCState *env)
> #endif
> /*
> * Register PCR to report POWERPC_EXCP_PRIV_REG instead of
> - * POWERPC_EXCP_INVAL_SPR.
> + * POWERPC_EXCP_INVAL_SPR in userspace. Permit hypervisor access.
> */
> - spr_register(env, SPR_PCR, "PCR",
> + spr_register_hv(env, SPR_PCR, "PCR",
> SPR_NOACCESS, SPR_NOACCESS,
> SPR_NOACCESS, SPR_NOACCESS,
> + &spr_read_generic, &spr_write_pcr,
> 0x00000000);
> }
>
--
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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