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.
> ---
> 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)
> {
> /*
--
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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