* Re: [Qemu-devel] [PATCH v2 1/2] ppc64: Rudimentary Support for extra page sizes on server CPUs
[not found] <1337054780.6727.60.camel@pasglop>
2012-05-21 2:01 ` [Qemu-devel] ppc: CPU reset must flush translation buffer Benjamin Herrenschmidt
@ 2012-05-21 7:39 ` Alexander Graf
1 sibling, 0 replies; 6+ messages in thread
From: Alexander Graf @ 2012-05-21 7:39 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: qemu-ppc, kvm list, kvm-ppc, QEMU Developers
On 15.05.2012, at 06:06, Benjamin Herrenschmidt wrote:
> More recent Power server chips (i.e. based on the 64 bit hash MMU)
> support more than just the traditional 4k and 16M page sizes. This
> can get quite complicated, because which page sizes are supported,
> which combinations are supported within an MMU segment and how these
> page sizes are encoded both in the SLB entry and the hash PTE can vary
> depending on the CPU model (they are not specified by the
> architecture). In addition the firmware or hypervisor may not permit
> use of certain page sizes, for various reasons. Whether various page
> sizes are supported on KVM, for example, depends on whether the PR or
> HV variant of KVM is in use, and on the page size of the memory
> backing the guest's RAM.
>
> This patch adds information to the CPUState and cpu defs to describe
> the supported page sizes and encodings. Since TCG does not yet
> support any extended page sizes, we just set this to NULL in the
> static CPU definitions, expanding this to the default 4k and 16M page
> sizes when we initialize the cpu state. When using KVM, however, we
> instead determine available page sizes using the new
> KVM_PPC_GET_SMMU_INFO call. For old kernels without that call, we use
> some defaults, with some guesswork which should do the right thing for
> existing HV and PR implementations. The fallback might not be correct
> for future versions, but that's ok, because they'll have
> KVM_PPC_GET_SMMU_INFO.
>
>
> Signed-off-by: Benjamin Herrenschmidt <
> benh@kernel.crashing.org
> >
> Signed-off-by: David Gibson <
> david@gibson.dropbear.id.au
> >
> ---
> v2: - Passes checkpatch now (with the exception of the kernel header
> bit which will eventually be replaced by the real thing when
> it goes upstream).
> - Moved back some fixes that were incorrectly located in the
> second patch (such as setting slb_size)
> - Fix some issues when using "PR" KVM without proper support
> for 1T segments
>
> Note: I kept the caching. It's not a "hot" path but still, it's a
> lot of mess to do for every CPU (and we routinely have a bunch
> on those power machines), in the end it adds up ...
>
> linux-headers/linux/kvm.h | 26 ++++++
> target-ppc/cpu.h | 31 +++++++
> target-ppc/helper.c | 7 ++
> target-ppc/kvm.c | 210 +++++++++++++++++++++++++++++++++++++++++++
> target-ppc/kvm_ppc.h | 5 +
> target-ppc/translate_init.c | 21 +++++
> 6 files changed, 300 insertions(+), 0 deletions(-)
>
> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> index ee7bd9c..015b6db 100644
> --- a/linux-headers/linux/kvm.h
> +++ b/linux-headers/linux/kvm.h
>
Please split Linux kernel header updates into their own patch, so I can easily redo them when necessary.
Also, you sent this mail to the wrong mailing lists - it's a QEMU patch :). CC'ing the correct ones.
> @@ -449,6 +449,30 @@ struct kvm_ppc_pvinfo {
> __u8 pad[108];
> };
>
> +/* for KVM_PPC_GET_SMMU_INFO */
> +#define KVM_PPC_PAGE_SIZES_MAX_SZ 8
> +
> +struct kvm_ppc_one_page_size {
> + __u32 page_shift; /* Page shift (or 0) */
> + __u32 pte_enc; /* Encoding in the HPTE (>>12) */
> +};
> +
> +struct kvm_ppc_one_seg_page_size {
> + __u32 page_shift; /* Base page shift of segment (or 0) */
> + __u32 slb_enc; /* SLB encoding for BookS */
> + struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ];
> +};
> +
> +#define KVM_PPC_PAGE_SIZES_REAL 0x00000001
> +#define KVM_PPC_1T_SEGMENTS 0x00000002
> +
> +struct kvm_ppc_smmu_info {
> + __u64 flags;
> + __u32 slb_size;
> + __u32 pad;
> + struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ];
> +};
> +
> #define KVMIO 0xAE
>
> /* machine type bits, to be used as argument to KVM_CREATE_VM */
> @@ -789,6 +813,8 @@ struct kvm_s390_ucas_mapping {
> /* Available with KVM_CAP_PCI_2_3 */
> #define KVM_ASSIGN_SET_INTX_MASK _IOW(KVMIO, 0xa4, \
> struct kvm_assigned_pci_dev)
> +/* Available with KVM_CAP_PPC_GET_SMMU_INFO */
> +#define KVM_PPC_GET_SMMU_INFO _IOR(KVMIO, 0xa5, struct kvm_ppc_smmu_info)
>
> /*
> * ioctls for vcpu fds
> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
> index 84c9674..3ed75ac 100644
> --- a/target-ppc/cpu.h
> +++ b/target-ppc/cpu.h
> @@ -119,6 +119,8 @@ enum powerpc_mmu_t {
> POWERPC_MMU_620 = POWERPC_MMU_64 | 0x00000002,
> /* Architecture 2.06 variant */
> POWERPC_MMU_2_06 = POWERPC_MMU_64 | POWERPC_MMU_1TSEG | 0x00000003,
> + /* Architecture 2.06 "degraded" (no 1T segments) */
> + POWERPC_MMU_2_06d = POWERPC_MMU_64 | 0x00000003,
> #endif /* defined(TARGET_PPC64) */
> };
>
> @@ -874,6 +876,29 @@ enum {
> #define DBELL_PIRTAG_MASK 0x3fff
>
> /*****************************************************************************/
> +/* Segment page size information, used by recent hash MMUs
> + * The format of this structure mirrors kvm_ppc_smmu_info
> + */
> +
> +#define PPC_PAGE_SIZES_MAX_SZ 8
> +
> +struct ppc_one_page_size {
> + uint32_t page_shift; /* Page shift (or 0) */
> + uint32_t pte_enc; /* Encoding in the HPTE (>>12) */
> +};
> +
> +struct ppc_one_seg_page_size {
> + uint32_t page_shift; /* Base page shift of segment (or 0) */
> + uint32_t slb_enc; /* SLB encoding for BookS */
> + struct ppc_one_page_size enc[PPC_PAGE_SIZES_MAX_SZ];
> +};
> +
> +struct ppc_segment_page_sizes {
> + struct ppc_one_seg_page_size sps[PPC_PAGE_SIZES_MAX_SZ];
> +};
> +
> +
> +/*****************************************************************************/
> /* The whole PowerPC CPU context */
> #define NB_MMU_MODES 3
>
> @@ -889,6 +914,9 @@ struct ppc_def_t {
> powerpc_input_t bus_model;
> uint32_t flags;
> int bfd_mach;
> +#if defined(TARGET_PPC64)
> + const struct ppc_segment_page_sizes *sps;
> +#endif
> void (*init_proc)(CPUPPCState *env);
> int (*check_pow)(CPUPPCState *env);
> };
> @@ -1012,6 +1040,9 @@ struct CPUPPCState {
> uint32_t flags;
> uint64_t insns_flags;
> uint64_t insns_flags2;
> +#if defined(TARGET_PPC64)
> + struct ppc_segment_page_sizes sps;
> +#endif
>
> #if defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY)
> target_phys_addr_t vpa;
> diff --git a/target-ppc/helper.c b/target-ppc/helper.c
> index e97e496..833d948 100644
> --- a/target-ppc/helper.c
> +++ b/target-ppc/helper.c
> @@ -1617,6 +1617,7 @@ void dump_mmu(FILE *f, fprintf_function cpu_fprintf, CPUPPCState *env)
> #if defined(TARGET_PPC64)
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> mmubooks_dump_mmu(f, cpu_fprintf, env);
> break;
> #endif
> @@ -1647,6 +1648,7 @@ static inline int check_physical(CPUPPCState *env, mmu_ctx_t *ctx,
> case POWERPC_MMU_620:
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> /* Real address are 60 bits long */
> ctx->raddr &= 0x0FFFFFFFFFFFFFFFULL;
> ctx->prot |= PAGE_WRITE;
> @@ -1727,6 +1729,7 @@ int get_physical_address (CPUPPCState *env, mmu_ctx_t *ctx, target_ulong eaddr,
> case POWERPC_MMU_620:
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> #endif
> if (ret < 0) {
> /* We didn't match any BAT entry or don't have BATs */
> @@ -1867,6 +1870,7 @@ int cpu_ppc_handle_mmu_fault (CPUPPCState *env, target_ulong address, int rw,
> case POWERPC_MMU_620:
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> #endif
> env->exception_index = POWERPC_EXCP_ISI;
> env->error_code = 0x40000000;
> @@ -1977,6 +1981,7 @@ int cpu_ppc_handle_mmu_fault (CPUPPCState *env, target_ulong address, int rw,
> case POWERPC_MMU_620:
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> #endif
> env->exception_index = POWERPC_EXCP_DSI;
> env->error_code = 0;
> @@ -2299,6 +2304,7 @@ void ppc_tlb_invalidate_all (CPUPPCState *env)
> case POWERPC_MMU_620:
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> #endif /* defined(TARGET_PPC64) */
> tlb_flush(env, 1);
> break;
> @@ -2367,6 +2373,7 @@ void ppc_tlb_invalidate_one (CPUPPCState *env, target_ulong addr)
> case POWERPC_MMU_620:
> case POWERPC_MMU_64B:
> case POWERPC_MMU_2_06:
> + case POWERPC_MMU_2_06d:
> /* tlbie invalidate TLBs for all segments */
> /* XXX: given the fact that there are too many segments to invalidate,
> * and we still don't have a tlb_flush_mask(env, n, mask) in QEMU,
> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> index 0ab7630..2100cb9 100644
> --- a/target-ppc/kvm.c
> +++ b/target-ppc/kvm.c
> @@ -18,6 +18,7 @@
> #include <sys/types.h>
> #include <sys/ioctl.h>
> #include <sys/mman.h>
> +#include <sys/vfs.h>
>
> #include <linux/kvm.h>
>
> @@ -167,10 +168,219 @@ static int kvm_booke206_tlb_init(CPUPPCState *env)
> return 0;
> }
>
> +
> +#if defined(TARGET_PPC64)
> +static void kvm_get_fallback_smmu_info(CPUPPCState *env,
> + struct kvm_ppc_smmu_info *info)
> +{
> + memset(info, 0, sizeof(*info));
> +
> + /* We don't have the new KVM_PPC_GET_SMMU_INFO ioctl, so
> + * need to "guess" what the supported page sizes are.
> + *
> + * For that to work we make a few assumptions:
> + *
> + * - If KVM_CAP_PPC_GET_PVINFO is supported we are running "PR"
> + * KVM which only supports 4K and 16M pages, but supports them
> + * regardless of the backing store characteritics. We also don't
> + * support 1T segments.
> + *
> + * This is safe as if HV KVM ever supports that capability or PR
> + * KVM grows supports for more page/segment sizes, those versions
> + * will have implemented KVM_CAP_PPC_GET_SMMU_INFO and thus we
> + * will not hit this fallback
> + *
> + * - Else we are running HV KVM. This means we only support page
> + * sizes that fit in the backing store. Additionally we only
> + * advertize 64K pages if the processor is ARCH 2.06 and we assume
> + * P7 encodings for the SLB and hash table. Here too, we assume
> + * support for any newer processor will mean a kernel that
> + * implements KVM_CAP_PPC_GET_SMMU_INFO and thus doesn't hit
> + * this fallback.
> + */
> + if (kvm_check_extension(env->kvm_state, KVM_CAP_PPC_GET_PVINFO)) {
> + /* No flags */
> + info->flags = 0;
> + info->slb_size = 64;
> +
> + /* Standard 4k base page size segment */
> + info->sps[0].page_shift = 12;
> + info->sps[0].slb_enc = 0;
> + info->sps[0].enc[0].page_shift = 12;
> + info->sps[0].enc[0].pte_enc = 0;
> +
> + /* Standard 16M large page size segment */
> + info->sps[1].page_shift = 24;
> + info->sps[1].slb_enc = SLB_VSID_L;
> + info->sps[1].enc[0].page_shift = 24;
> + info->sps[1].enc[0].pte_enc = 0;
> + } else {
> + int i = 0;
> +
> + /* HV KVM has backing store size restrictions */
> + info->flags = KVM_PPC_PAGE_SIZES_REAL;
> +
> + if (env->mmu_model & POWERPC_MMU_1TSEG) {
> + info->flags |= KVM_PPC_1T_SEGMENTS;
> + }
> +
> + if (env->mmu_model == POWERPC_MMU_2_06) {
> + info->slb_size = 32;
> + } else {
> + info->slb_size = 64;
> + }
> +
> + /* Standard 4k base page size segment */
> + info->sps[i].page_shift = 12;
> + info->sps[i].slb_enc = 0;
> + info->sps[i].enc[0].page_shift = 12;
> + info->sps[i].enc[0].pte_enc = 0;
> + i++;
> +
> + /* 64K on MMU 2.06 */
> + if (env->mmu_model == POWERPC_MMU_2_06) {
> + info->sps[i].page_shift = 16;
> + info->sps[i].slb_enc = 0x110;
> + info->sps[i].enc[0].page_shift = 16;
> + info->sps[i].enc[0].pte_enc = 1;
> + i++;
> + }
> +
> + /* Standard 16M large page size segment */
> + info->sps[i].page_shift = 24;
> + info->sps[i].slb_enc = SLB_VSID_L;
> + info->sps[i].enc[0].page_shift = 24;
> + info->sps[i].enc[0].pte_enc = 0;
> + }
> +}
> +
> +static void kvm_get_smmu_info(CPUPPCState *env, struct kvm_ppc_smmu_info *info)
> +{
> +#ifdef KVM_CAP_PPC_GET_SMMU_INFO
>
No need to for the #ifdef anymore, because we're syncing the headers now.
> + int ret;
> +
> + if (kvm_check_extension(env->kvm_state, KVM_CAP_PPC_GET_SMMU_INFO)) {
> + ret = kvm_vm_ioctl(env->kvm_state, KVM_PPC_GET_SMMU_INFO, info);
> + if (ret == 0) {
> + return;
> + }
> + }
> +#endif /* KVM_CAP_PPC_GET_SMMU_INFO */
> +
> + kvm_get_fallback_smmu_info(env, info);
> +}
> +
> +static long getrampagesize(void)
> +{
> + struct statfs fs;
> + int ret;
> +
> + if (!mem_path) {
> + /* guest RAM is backed by normal anonymous pages */
> + return getpagesize();
> + }
> +
> + do {
> + ret = statfs(mem_path, &fs);
> + } while (ret != 0 && errno == EINTR);
> +
> + if (ret != 0) {
> + fprintf(stderr, "Couldn't statfs() memory path: %s\n",
> + strerror(errno));
> + exit(1);
> + }
> +
> +#define HUGETLBFS_MAGIC 0x958458f6
> +
> + if (fs.f_type != HUGETLBFS_MAGIC) {
> + /* Explicit mempath, but it's ordinary pages */
> + return getpagesize();
> + }
> +
> + /* It's hugepage, return the huge page size */
> + return fs.f_bsize;
> +}
> +
> +static bool kvm_valid_page_size(uint32_t flags, long rampgsize, uint32_t shift)
> +{
> + if (!(flags & KVM_PPC_PAGE_SIZES_REAL)) {
> + return true;
> + }
> +
> + return (1ul << shift) <= rampgsize;
> +}
> +
> +static void kvm_fixup_page_sizes(CPUPPCState *env)
> +{
> + static struct kvm_ppc_smmu_info smmu_info;
> + static bool has_smmu_info;
> + long rampagesize;
> + int iq, ik, jq, jk;
> +
> + /* We only handle page sizes for 64-bit server guests for now */
> + if (!(env->mmu_model & POWERPC_MMU_64)) {
> + return;
> + }
> +
> + /* Collect MMU info from kernel if not already */
> + if (!has_smmu_info) {
> + kvm_get_smmu_info(env, &smmu_info);
> + has_smmu_info = true;
> + }
> +
> + rampagesize = getrampagesize();
> +
> + /* Convert to QEMU form */
> + memset(&env->sps, 0, sizeof(env->sps));
> +
> + for (ik = iq = 0; ik < KVM_PPC_PAGE_SIZES_MAX_SZ; ik++) {
> + struct ppc_one_seg_page_size *qsps = &env->sps.sps[iq];
> + struct kvm_ppc_one_seg_page_size *ksps = &smmu_info.sps[ik];
> +
> + if (!kvm_valid_page_size(smmu_info.flags, rampagesize,
> + ksps->page_shift)) {
> + continue;
> + }
> + qsps->page_shift = ksps->page_shift;
> + qsps->slb_enc = ksps->slb_enc;
> + for (jk = jq = 0; jk < KVM_PPC_PAGE_SIZES_MAX_SZ; jk++) {
> + if (!kvm_valid_page_size(smmu_info.flags, rampagesize,
> + ksps->enc[jk].page_shift)) {
> + continue;
> + }
> + qsps->enc[jq].page_shift = ksps->enc[jk].page_shift;
> + qsps->enc[jq].pte_enc = ksps->enc[jk].pte_enc;
> + if (++jq >= PPC_PAGE_SIZES_MAX_SZ) {
> + break;
> + }
> + }
> + if (++iq >= PPC_PAGE_SIZES_MAX_SZ) {
> + break;
> + }
> + }
> + env->slb_nr = smmu_info.slb_size;
> + if (smmu_info.flags & KVM_PPC_1T_SEGMENTS) {
> + env->mmu_model |= POWERPC_MMU_1TSEG;
> + } else {
> + env->mmu_model &= ~POWERPC_MMU_1TSEG;
> + }
> +}
> +#else /* defined (TARGET_PPC64) */
> +
> +static inline void kvm_fixup_page_sizes(CPUPPCState *env)
> +{
> +}
> +
> +#endif /* !defined (TARGET_PPC64) */
> +
> int kvm_arch_init_vcpu(CPUPPCState *cenv)
> {
> int ret;
>
> + /* Gather server mmu info from KVM and update the CPU state*/
>
Missing space? :)
Alex
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