On 03/01/17 10:34, David Gibson wrote: > On Thu, Dec 22, 2016 at 04:22:11PM +1100, Alexey Kardashevskiy wrote: >> getrampagesize() returns the largest supported page size and mainly >> used to know if huge pages are enabled. >> >> However is implemented in target-ppc/kvm.c and not available >> in TCG or other architectures. >> >> This renames and moves gethugepagesize() to mmap-alloc.c where >> fd-based analog of it is already implemented. This renames and moves >> getrampagesize() to exec.c as it seems to be the common place for >> helpers like this. >> >> This first user for it is going to be a spapr-pci-host-bridge which >> needs to know the largest RAM page size so the guest could try >> using bigger IOMMU pages to save memory. >> >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > > Reviewed-by: David Gibson <da...@gibson.dropbear.id.au> > > Seems sensible to me, but I'm not comfortable merging this via my tree > since it touches such core code. Probably should go via Paolo.
Paolo, ping?
>
>> ---
>> include/exec/ram_addr.h | 1 +
>> include/qemu/mmap-alloc.h | 2 +
>> exec.c | 82 ++++++++++++++++++++++++++++++++++++
>> target-ppc/kvm.c | 105
>> ++--------------------------------------------
>> util/mmap-alloc.c | 25 +++++++++++
>> 5 files changed, 113 insertions(+), 102 deletions(-)
>>
>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
>> index 54d7108a9e..3935cbcfcd 100644
>> --- a/include/exec/ram_addr.h
>> +++ b/include/exec/ram_addr.h
>> @@ -91,6 +91,7 @@ typedef struct RAMList {
>> } RAMList;
>> extern RAMList ram_list;
>>
>> +long qemu_getrampagesize(void);
>> ram_addr_t last_ram_offset(void);
>> void qemu_mutex_lock_ramlist(void);
>> void qemu_mutex_unlock_ramlist(void);
>> diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h
>> index 933c024ac5..50385e3f81 100644
>> --- a/include/qemu/mmap-alloc.h
>> +++ b/include/qemu/mmap-alloc.h
>> @@ -5,6 +5,8 @@
>>
>> size_t qemu_fd_getpagesize(int fd);
>>
>> +size_t qemu_mempath_getpagesize(const char *mem_path);
>> +
>> void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared);
>>
>> void qemu_ram_munmap(void *ptr, size_t size);
>> diff --git a/exec.c b/exec.c
>> index 08c558eecf..d73b477a70 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -32,6 +32,7 @@
>> #endif
>> #include "sysemu/kvm.h"
>> #include "sysemu/sysemu.h"
>> +#include "sysemu/numa.h"
>> #include "qemu/timer.h"
>> #include "qemu/config-file.h"
>> #include "qemu/error-report.h"
>> @@ -1218,6 +1219,87 @@ void qemu_mutex_unlock_ramlist(void)
>> }
>>
>> #ifdef __linux__
>> +/*
>> + * FIXME TOCTTOU: this iterates over memory backends' mem-path, which
>> + * may or may not name the same files / on the same filesystem now as
>> + * when we actually open and map them. Iterate over the file
>> + * descriptors instead, and use qemu_fd_getpagesize().
>> + */
>> +static int find_max_supported_pagesize(Object *obj, void *opaque)
>> +{
>> + char *mem_path;
>> + long *hpsize_min = opaque;
>> +
>> + if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND)) {
>> + mem_path = object_property_get_str(obj, "mem-path", NULL);
>> + if (mem_path) {
>> + long hpsize = qemu_mempath_getpagesize(mem_path);
>> + if (hpsize < *hpsize_min) {
>> + *hpsize_min = hpsize;
>> + }
>> + } else {
>> + *hpsize_min = getpagesize();
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +long qemu_getrampagesize(void)
>> +{
>> + long hpsize = LONG_MAX;
>> + long mainrampagesize;
>> + Object *memdev_root;
>> +
>> + if (mem_path) {
>> + mainrampagesize = qemu_mempath_getpagesize(mem_path);
>> + } else {
>> + mainrampagesize = getpagesize();
>> + }
>> +
>> + /* it's possible we have memory-backend objects with
>> + * hugepage-backed RAM. these may get mapped into system
>> + * address space via -numa parameters or memory hotplug
>> + * hooks. we want to take these into account, but we
>> + * also want to make sure these supported hugepage
>> + * sizes are applicable across the entire range of memory
>> + * we may boot from, so we take the min across all
>> + * backends, and assume normal pages in cases where a
>> + * backend isn't backed by hugepages.
>> + */
>> + memdev_root = object_resolve_path("/objects", NULL);
>> + if (memdev_root) {
>> + object_child_foreach(memdev_root, find_max_supported_pagesize,
>> &hpsize);
>> + }
>> + if (hpsize == LONG_MAX) {
>> + /* No additional memory regions found ==> Report main RAM page size
>> */
>> + return mainrampagesize;
>> + }
>> +
>> + /* If NUMA is disabled or the NUMA nodes are not backed with a
>> + * memory-backend, then there is at least one node using "normal" RAM,
>> + * so if its page size is smaller we have got to report that size
>> instead.
>> + */
>> + if (hpsize > mainrampagesize &&
>> + (nb_numa_nodes == 0 || numa_info[0].node_memdev == NULL)) {
>> + static bool warned;
>> + if (!warned) {
>> + error_report("Huge page support disabled (n/a for main
>> memory).");
>> + warned = true;
>> + }
>> + return mainrampagesize;
>> + }
>> +
>> + return hpsize;
>> +}
>> +#else
>> +long qemu_getrampagesize(void)
>> +{
>> + return getpagesize();
>> +}
>> +#endif
>> +
>> +#ifdef __linux__
>> static int64_t get_file_size(int fd)
>> {
>> int64_t size = lseek(fd, 0, SEEK_END);
>> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
>> index 6e91a4d8bb..e0abffa8ad 100644
>> --- a/target-ppc/kvm.c
>> +++ b/target-ppc/kvm.c
>> @@ -42,6 +42,7 @@
>> #include "trace.h"
>> #include "exec/gdbstub.h"
>> #include "exec/memattrs.h"
>> +#include "exec/ram_addr.h"
>> #include "sysemu/hostmem.h"
>> #include "qemu/cutils.h"
>> #if defined(TARGET_PPC64)
>> @@ -325,106 +326,6 @@ static void kvm_get_smmu_info(PowerPCCPU *cpu, struct
>> kvm_ppc_smmu_info *info)
>> kvm_get_fallback_smmu_info(cpu, info);
>> }
>>
>> -static long gethugepagesize(const char *mem_path)
>> -{
>> - struct statfs fs;
>> - int ret;
>> -
>> - 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;
>> -}
>> -
>> -/*
>> - * FIXME TOCTTOU: this iterates over memory backends' mem-path, which
>> - * may or may not name the same files / on the same filesystem now as
>> - * when we actually open and map them. Iterate over the file
>> - * descriptors instead, and use qemu_fd_getpagesize().
>> - */
>> -static int find_max_supported_pagesize(Object *obj, void *opaque)
>> -{
>> - char *mem_path;
>> - long *hpsize_min = opaque;
>> -
>> - if (object_dynamic_cast(obj, TYPE_MEMORY_BACKEND)) {
>> - mem_path = object_property_get_str(obj, "mem-path", NULL);
>> - if (mem_path) {
>> - long hpsize = gethugepagesize(mem_path);
>> - if (hpsize < *hpsize_min) {
>> - *hpsize_min = hpsize;
>> - }
>> - } else {
>> - *hpsize_min = getpagesize();
>> - }
>> - }
>> -
>> - return 0;
>> -}
>> -
>> -static long getrampagesize(void)
>> -{
>> - long hpsize = LONG_MAX;
>> - long mainrampagesize;
>> - Object *memdev_root;
>> -
>> - if (mem_path) {
>> - mainrampagesize = gethugepagesize(mem_path);
>> - } else {
>> - mainrampagesize = getpagesize();
>> - }
>> -
>> - /* it's possible we have memory-backend objects with
>> - * hugepage-backed RAM. these may get mapped into system
>> - * address space via -numa parameters or memory hotplug
>> - * hooks. we want to take these into account, but we
>> - * also want to make sure these supported hugepage
>> - * sizes are applicable across the entire range of memory
>> - * we may boot from, so we take the min across all
>> - * backends, and assume normal pages in cases where a
>> - * backend isn't backed by hugepages.
>> - */
>> - memdev_root = object_resolve_path("/objects", NULL);
>> - if (memdev_root) {
>> - object_child_foreach(memdev_root, find_max_supported_pagesize,
>> &hpsize);
>> - }
>> - if (hpsize == LONG_MAX) {
>> - /* No additional memory regions found ==> Report main RAM page size
>> */
>> - return mainrampagesize;
>> - }
>> -
>> - /* If NUMA is disabled or the NUMA nodes are not backed with a
>> - * memory-backend, then there is at least one node using "normal" RAM,
>> - * so if its page size is smaller we have got to report that size
>> instead.
>> - */
>> - if (hpsize > mainrampagesize &&
>> - (nb_numa_nodes == 0 || numa_info[0].node_memdev == NULL)) {
>> - static bool warned;
>> - if (!warned) {
>> - error_report("Huge page support disabled (n/a for main
>> memory).");
>> - warned = true;
>> - }
>> - return mainrampagesize;
>> - }
>> -
>> - return hpsize;
>> -}
>> -
>> static bool kvm_valid_page_size(uint32_t flags, long rampgsize, uint32_t
>> shift)
>> {
>> if (!(flags & KVM_PPC_PAGE_SIZES_REAL)) {
>> @@ -454,7 +355,7 @@ static void kvm_fixup_page_sizes(PowerPCCPU *cpu)
>> has_smmu_info = true;
>> }
>>
>> - rampagesize = getrampagesize();
>> + rampagesize = qemu_getrampagesize();
>>
>> /* Convert to QEMU form */
>> memset(&env->sps, 0, sizeof(env->sps));
>> @@ -2177,7 +2078,7 @@ uint64_t kvmppc_rma_size(uint64_t current_size,
>> unsigned int hash_shift)
>> /* Find the largest hardware supported page size that's less than
>> * or equal to the (logical) backing page size of guest RAM */
>> kvm_get_smmu_info(POWERPC_CPU(first_cpu), &info);
>> - rampagesize = getrampagesize();
>> + rampagesize = qemu_getrampagesize();
>> best_page_shift = 0;
>>
>> for (i = 0; i < KVM_PPC_PAGE_SIZES_MAX_SZ; i++) {
>> diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
>> index 5a85aa3c89..564c79109c 100644
>> --- a/util/mmap-alloc.c
>> +++ b/util/mmap-alloc.c
>> @@ -39,6 +39,31 @@ size_t qemu_fd_getpagesize(int fd)
>> return getpagesize();
>> }
>>
>> +size_t qemu_mempath_getpagesize(const char *mem_path)
>> +{
>> +#ifdef CONFIG_LINUX
>> + struct statfs fs;
>> + int ret;
>> +
>> + 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);
>> + }
>> +
>> + if (fs.f_type == HUGETLBFS_MAGIC) {
>> + /* It's hugepage, return the huge page size */
>> + return fs.f_bsize;
>> + }
>> +#endif
>> +
>> + return getpagesize();
>> +}
>> +
>> void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
>> {
>> /*
>
--
Alexey
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