On Tue, 17 Apr 2018 17:17:14 +1000 David Gibson <da...@gibson.dropbear.id.au> wrote:
> Current POWER cpus allow for a VRMA, a special mapping which describes a > guest's view of memory when in real mode (MMU off, from the guest's point > of view). Older cpus didn't have that which meant that to support a guest > a special host-contiguous region of memory was needed to give the guest its > Real Mode Area (RMA). > > This was useful in the early days of KVM on Power to allow it to be tested > on PowerPC 970 chips as used in Macintosh G5 machines. Now, however, those > machines are so old as to be irrelevant, and the host kernel has long since > dropped support for this mode. It hasn't been tested in ages either. > > So, to simplify the code, drop the support from qemu as well. > So this could possibly break TCG guests with 970, which happens to be bootable with the current code ? $ cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.9 (Santiago) $ cat /proc/cpuinfo processor : 0 cpu : PPC970, altivec supported clock : 1000.000000MHz revision : 2.2 (pvr 0039 0202) timebase : 512000000 platform : pSeries model : IBM pSeries (emulated by qemu) machine : CHRP IBM pSeries (emulated by qemu) I guess nobody uses this setup, but my understanding is that some rules must be followed when it comes to removing something that works. https://wiki.qemu.org/Features/LegacyRemoval#Rules_for_removing_an_interface Maybe add a warning if 970 is used, and turn it into an error in two releases along with this patch ? > As well as the code for handling contiguous RMAs, we can remove some > code to set the HIOR register, which existed on 970 but not on the > current and supported CPUs. > > Signed-off-by: David Gibson <da...@gibson.dropbear.id.au> > --- > hw/ppc/spapr.c | 61 > +++++++++++++++---------------------------------- > hw/ppc/spapr_cpu_core.c | 2 -- > target/ppc/kvm.c | 36 ----------------------------- > target/ppc/kvm_ppc.h | 6 ----- > 4 files changed, 19 insertions(+), 86 deletions(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 81b50af3b5..fbb2c6752c 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -2376,9 +2376,6 @@ static void spapr_machine_init(MachineState *machine) > int i; > MemoryRegion *sysmem = get_system_memory(); > MemoryRegion *ram = g_new(MemoryRegion, 1); > - MemoryRegion *rma_region; > - void *rma = NULL; > - hwaddr rma_alloc_size; > hwaddr node0_size = spapr_node0_size(machine); > long load_limit, fw_size; > char *filename; > @@ -2417,40 +2414,28 @@ static void spapr_machine_init(MachineState *machine) > exit(1); > } > > - /* Allocate RMA if necessary */ > - rma_alloc_size = kvmppc_alloc_rma(&rma); > + spapr->rma_size = node0_size; > > - if (rma_alloc_size == -1) { > - error_report("Unable to create RMA"); > - exit(1); > + /* With KVM, we don't actually know whether KVM supports an > + * unbounded RMA (PR KVM) or is limited by the hash table size (HV > + * KVM using VRMA), so we always assume the latter > + * > + * In that case, we also limit the initial allocations for RTAS > + * etc... to 256M since we have no way to know what the VRMA size > + * is going to be as it depends on the size of the hash table > + * isn't determined yet. > + */ > + if (kvm_enabled()) { > + spapr->vrma_adjust = 1; > + spapr->rma_size = MIN(spapr->rma_size, 0x10000000); > } > > - if (rma_alloc_size && (rma_alloc_size < node0_size)) { > - spapr->rma_size = rma_alloc_size; > - } else { > - spapr->rma_size = node0_size; > - > - /* With KVM, we don't actually know whether KVM supports an > - * unbounded RMA (PR KVM) or is limited by the hash table size > - * (HV KVM using VRMA), so we always assume the latter > - * > - * In that case, we also limit the initial allocations for RTAS > - * etc... to 256M since we have no way to know what the VRMA size > - * is going to be as it depends on the size of the hash table > - * isn't determined yet. > - */ > - if (kvm_enabled()) { > - spapr->vrma_adjust = 1; > - spapr->rma_size = MIN(spapr->rma_size, 0x10000000); > - } > - > - /* Actually we don't support unbounded RMA anymore since we > - * added proper emulation of HV mode. The max we can get is > - * 16G which also happens to be what we configure for PAPR > - * mode so make sure we don't do anything bigger than that > - */ > - spapr->rma_size = MIN(spapr->rma_size, 0x400000000ull); > - } > + /* Actually we don't support unbounded RMA anymore since we > + * added proper emulation of HV mode. The max we can get is > + * 16G which also happens to be what we configure for PAPR > + * mode so make sure we don't do anything bigger than that > + */ > + spapr->rma_size = MIN(spapr->rma_size, 0x400000000ull); > > if (spapr->rma_size > node0_size) { > error_report("Numa node 0 has to span the RMA (%#08"HWADDR_PRIx")", > @@ -2508,14 +2493,6 @@ static void spapr_machine_init(MachineState *machine) > machine->ram_size); > memory_region_add_subregion(sysmem, 0, ram); > > - if (rma_alloc_size && rma) { > - rma_region = g_new(MemoryRegion, 1); > - memory_region_init_ram_ptr(rma_region, NULL, "ppc_spapr.rma", > - rma_alloc_size, rma); > - vmstate_register_ram_global(rma_region); > - memory_region_add_subregion(sysmem, 0, rma_region); > - } > - > /* initialize hotplug memory address space */ > if (machine->ram_size < machine->maxram_size) { > ram_addr_t hotplug_mem_size = machine->maxram_size - > machine->ram_size; > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c > index aa17626cda..f39d99a8da 100644 > --- a/hw/ppc/spapr_cpu_core.c > +++ b/hw/ppc/spapr_cpu_core.c > @@ -36,8 +36,6 @@ static void spapr_cpu_reset(void *opaque) > * using an RTAS call */ > cs->halted = 1; > > - env->spr[SPR_HIOR] = 0; > - > /* Disable Power-saving mode Exit Cause exceptions for the CPU. > * This can cause issues when rebooting the guest if a secondary > * is awaken */ > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c > index 6de59c5b21..51177a8e00 100644 > --- a/target/ppc/kvm.c > +++ b/target/ppc/kvm.c > @@ -2159,42 +2159,6 @@ void kvmppc_hint_smt_possible(Error **errp) > > > #ifdef TARGET_PPC64 > -off_t kvmppc_alloc_rma(void **rma) > -{ > - off_t size; > - int fd; > - struct kvm_allocate_rma ret; > - > - /* If cap_ppc_rma == 0, contiguous RMA allocation is not supported > - * if cap_ppc_rma == 1, contiguous RMA allocation is supported, but > - * not necessary on this hardware > - * if cap_ppc_rma == 2, contiguous RMA allocation is needed on this > hardware > - * > - * FIXME: We should allow the user to force contiguous RMA > - * allocation in the cap_ppc_rma==1 case. > - */ > - if (cap_ppc_rma < 2) { > - return 0; > - } > - > - fd = kvm_vm_ioctl(kvm_state, KVM_ALLOCATE_RMA, &ret); > - if (fd < 0) { > - fprintf(stderr, "KVM: Error on KVM_ALLOCATE_RMA: %s\n", > - strerror(errno)); > - return -1; > - } > - > - size = MIN(ret.rma_size, 256ul << 20); > - > - *rma = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); > - if (*rma == MAP_FAILED) { > - fprintf(stderr, "KVM: Error mapping RMA: %s\n", strerror(errno)); > - return -1; > - }; > - > - return size; > -} > - > uint64_t kvmppc_rma_size(uint64_t current_size, unsigned int hash_shift) > { > struct kvm_ppc_smmu_info info; > diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h > index 4d2789eef6..e2840e1d33 100644 > --- a/target/ppc/kvm_ppc.h > +++ b/target/ppc/kvm_ppc.h > @@ -37,7 +37,6 @@ target_ulong kvmppc_configure_v3_mmu(PowerPCCPU *cpu, > bool radix, bool gtse, > uint64_t proc_tbl); > #ifndef CONFIG_USER_ONLY > -off_t kvmppc_alloc_rma(void **rma); > bool kvmppc_spapr_use_multitce(void); > int kvmppc_spapr_enable_inkernel_multitce(void); > void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t page_shift, > @@ -188,11 +187,6 @@ static inline target_ulong > kvmppc_configure_v3_mmu(PowerPCCPU *cpu, > } > > #ifndef CONFIG_USER_ONLY > -static inline off_t kvmppc_alloc_rma(void **rma) > -{ > - return 0; > -} > - > static inline bool kvmppc_spapr_use_multitce(void) > { > return false;
