From c137583fc3e2be391cfe9b3ccd0766989ca9bc49 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 29 Sep 2015 03:19:03 +0200 Subject: [PATCH 01/44] target-ppc: fix hugepage support when using memory-backend-file Message-id: <1443496743-29679-1-git-send-email-dgibson@redhat.com> Patchwork-id: 67966 O-Subject: [RHEL7.2 qemu-kvm-rhev PATCH] target-ppc: fix hugepage support when using memory-backend-file Bugzilla: 1279387 RH-Acked-by: Paolo Bonzini RH-Acked-by: Laurent Vivier RH-Acked-by: Thomas Huth From: David Gibson Current PPC code relies on -mem-path being used in order for hugepage support to be detected. With the introduction of MemoryBackendFile we can now handle this via: -object memory-file-backend,mem-path=...,id=hugemem0 \ -numa node,id=mem0,memdev=hugemem0 Management tools like libvirt treat the 2 approaches as interchangeable in some cases, which can lead to user-visible regressions even for previously supported guest configurations. Fix these by also iterating through any configured memory backends that may be backed by hugepages. Since the old code assumed hugepages always backed the entirety of guest memory, play it safe an pick the minimum across the max pages sizes for all backends, even ones that aren't backed by hugepages. Signed-off-by: Michael Roth Reviewed-by: David Gibson Signed-off-by: Alexander Graf (cherry picked from commit 2d103aae876518a91636ad6f4a4d866269c0d953) Signed-off-by: Miroslav Rezanina Conflicts: target-ppc/kvm.c Contextual conflict in the #includes because downstream doesn't have 4c66375. Signed-off-by: David Gibson --- target-ppc/kvm.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 51 insertions(+), 6 deletions(-) diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c index 9a7f244..5dcde8c 100644 --- a/target-ppc/kvm.c +++ b/target-ppc/kvm.c @@ -39,6 +39,7 @@ #include "sysemu/watchdog.h" #include "trace.h" #include "exec/gdbstub.h" +#include "sysemu/hostmem.h" //#define DEBUG_KVM @@ -302,16 +303,11 @@ static void kvm_get_smmu_info(PowerPCCPU *cpu, struct kvm_ppc_smmu_info *info) kvm_get_fallback_smmu_info(cpu, info); } -static long getrampagesize(void) +static long gethugepagesize(const char *mem_path) { 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); @@ -333,6 +329,55 @@ static long getrampagesize(void) return fs.f_bsize; } +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; + Object *memdev_root; + + if (mem_path) { + return gethugepagesize(mem_path); + } + + /* 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) { + return getpagesize(); + } + + object_child_foreach(memdev_root, find_max_supported_pagesize, &hpsize); + + return (hpsize == LONG_MAX) ? getpagesize() : hpsize; +} + static bool kvm_valid_page_size(uint32_t flags, long rampgsize, uint32_t shift) { if (!(flags & KVM_PPC_PAGE_SIZES_REAL)) { -- 1.8.3.1