From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60155) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wn2i2-0008KY-CD for qemu-devel@nongnu.org; Wed, 21 May 2014 05:21:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wn2hw-0001og-3H for qemu-devel@nongnu.org; Wed, 21 May 2014 05:21:14 -0400 Message-ID: <537C7002.5090100@suse.de> Date: Wed, 21 May 2014 11:21:06 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1400660862-20455-1-git-send-email-aik@ozlabs.ru> <1400660862-20455-9-git-send-email-aik@ozlabs.ru> In-Reply-To: <1400660862-20455-9-git-send-email-aik@ozlabs.ru> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 8/9] spapr: Implement processor compatibility in ibm, client-architecture-support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexey Kardashevskiy , qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org On 21.05.14 10:27, Alexey Kardashevskiy wrote: > Modern Linux kernels support last POWERPC CPUs so when a kernel boots, > in most cases it can find a matching cpu_spec in the kernel's cpu_specs > list. However if the kernel is quite old, it may be missing a definition > of the actual CPU. To provide an ability for old kernels to work on modern > hardware, a Processor Compatibility Mode has been introduced > by the PowerISA specification. > > From the hardware prospective, it is supported by the Processor > Compatibility Register (PCR) which is defined in PowerISA. The register > enables one of the compatibility modes (2.05/2.06/2.07). > Since PCR is a hypervisor privileged register and cannot be > directly accessed from the guest, the mode selection is done via > ibm,client-architecture-support (CAS) RTAS call using which the guest > specifies what "raw" and "architected" CPU versions it supports. > QEMU works out the best match, changes a "cpu-version" property of > every CPU and notifies the guest about the change by setting these > properties in the buffer passed as a response on a custom H_CAS hypercall. > > This implements ibm,client-architecture-support parameters parsing > (now only for PVRs) and cooks the device tree diff with new values for > "cpu-version", "ibm,ppc-interrupt-server#s" and > "ibm,ppc-interrupt-server#s" properties. > > Signed-off-by: Alexey Kardashevskiy > --- > hw/ppc/spapr.c | 4 ++- > hw/ppc/spapr_hcall.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > trace-events | 4 +++ > 3 files changed, 92 insertions(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 14c72d9..020426a 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -34,6 +34,7 @@ > #include "sysemu/kvm.h" > #include "kvm_ppc.h" > #include "mmu-hash64.h" > +#include "qom/cpu.h" > > #include "hw/boards.h" > #include "hw/ppc/ppc.h" > @@ -601,7 +602,8 @@ int spapr_h_cas_compose_response(target_ulong addr, target_ulong size) > _FDT((fdt_open_into(fdt_skel, fdt, size))); > g_free(fdt_skel); > > - /* Place to make changes to the tree */ > + /* Fix skeleton up */ > + _FDT((spapr_fixup_cpu_dt(fdt, spapr))); > > /* Pack resulting tree */ > _FDT((fdt_pack(fdt))); > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c > index 2f6aa5c..2e0a49c 100644 > --- a/hw/ppc/spapr_hcall.c > +++ b/hw/ppc/spapr_hcall.c > @@ -3,6 +3,9 @@ > #include "helper_regs.h" > #include "hw/ppc/spapr.h" > #include "mmu-hash64.h" > +#include "cpu-models.h" > +#include "trace.h" > +#include "kvm_ppc.h" > > struct SPRSyncState { > CPUState *cs; > @@ -752,12 +755,94 @@ out: > return ret; > } > > +#define get_compat_level(cpuver) ( \ > + ((cpuver) == CPU_POWERPC_LOGICAL_2_05) ? 2050 : \ > + ((cpuver) == CPU_POWERPC_LOGICAL_2_06) ? 2060 : \ > + ((cpuver) == CPU_POWERPC_LOGICAL_2_06_PLUS) ? 2061 : \ > + ((cpuver) == CPU_POWERPC_LOGICAL_2_07) ? 2070 : 0) > + > static target_ulong h_client_architecture_support(PowerPCCPU *cpu_, > sPAPREnvironment *spapr, > target_ulong opcode, > target_ulong *args) > { > target_ulong list = args[0]; > + PowerPCCPUClass *pcc_ = POWERPC_CPU_GET_CLASS(cpu_); > + CPUState *cs; > + bool cpu_match = false; > + unsigned old_cpu_version = cpu_->cpu_version; > + unsigned compat_lvl = 0, cpu_version = 0; > + unsigned max_lvl = get_compat_level(cpu_->max_compat); > + > + /* Parse PVR list */ > + for ( ; ; ) { > + uint32_t pvr, pvr_mask; > + > + pvr_mask = rtas_ld(list, 0); > + list += 4; > + pvr = rtas_ld(list, 0); > + list += 4; > + > + trace_spapr_cas_pvr_try(pvr); > + if (!max_lvl && > + ((cpu_->env.spr[SPR_PVR] & pvr_mask) == (pvr & pvr_mask))) { > + cpu_match = true; > + cpu_version = 0; > + } else if (pvr == cpu_->cpu_version) { > + cpu_match = true; > + cpu_version = cpu_->cpu_version; > + } else if (!cpu_match) { > + /* If it is a logical PVR, try to determine the highest level */ > + unsigned lvl = get_compat_level(pvr); > + if (lvl) { > + bool is205 = (pcc_->pcr_mask & PCR_COMPAT_2_05) && > + (lvl == get_compat_level(CPU_POWERPC_LOGICAL_2_05)); > + bool is206 = (pcc_->pcr_mask & PCR_COMPAT_2_06) && > + ((lvl == get_compat_level(CPU_POWERPC_LOGICAL_2_06)) || > + (lvl == get_compat_level(CPU_POWERPC_LOGICAL_2_06_PLUS))); > + > + if (is205 || is206) { > + if (!max_lvl) { > + /* User did not set the level, choose the highest */ > + if (compat_lvl <= lvl) { > + compat_lvl = lvl; > + cpu_version = pvr; > + } > + } else if (max_lvl >= lvl) { > + /* User chose the level, don't set higher than this */ > + compat_lvl = lvl; > + cpu_version = pvr; > + } > + } > + } > + } > + /* Terminator record */ > + if (~pvr_mask & pvr) { This loop can be used by the guest to stall QEMU for a long period of time, no? Better add a safety net check somewhere to allow for early abort. > + break; > + } > + } > + > + /* For the future use: here @list points to the first capability */ > + > + /* Parsing finished */ > + trace_spapr_cas_pvr(cpu_->cpu_version, cpu_match, > + cpu_version, pcc_->pcr_mask); > + > + /* Update CPUs */ > + if (old_cpu_version != cpu_version) { > + CPU_FOREACH(cs) { > + PowerPCCPU *cpu = POWERPC_CPU(cs); > + > + if (ppc_set_compat(cpu, cpu_version) < 0) { Please run the updates on the vcpu threads themselves. Alex