From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: [PATCH] kvm: Query KVM for available memory slots Date: Fri, 22 Nov 2013 12:12:44 -0700 Message-ID: <20131122191154.16705.42189.stgit@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org To: pbonzini@redhat.com, gleb@redhat.com, kvm@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2271 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755413Ab3KVTMq (ORCPT ); Fri, 22 Nov 2013 14:12:46 -0500 Sender: kvm-owner@vger.kernel.org List-ID: KVM reports the number of available memory slots (KVM_CAP_NR_MEMSLOTS) using the extension interface. Both x86 and s390 implement this, ARM and powerpc do not yet enable it. Convert the static slots array to be dynamically allocated, supporting more slots when available. Default to 32 when KVM_CAP_NR_MEMSLOTS is not implemented. The motivation for this change is to support more assigned devices, where memory mapped PCI MMIO BARs typically take one slot each. Signed-off-by: Alex Williamson --- kvm-all.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/kvm-all.c b/kvm-all.c index 4478969..63c4e9b 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -72,7 +72,8 @@ typedef struct kvm_dirty_log KVMDirtyLog; struct KVMState { - KVMSlot slots[32]; + KVMSlot *slots; + int nr_slots; int fd; int vmfd; int coalesced_mmio; @@ -125,7 +126,7 @@ static KVMSlot *kvm_alloc_slot(KVMState *s) { int i; - for (i = 0; i < ARRAY_SIZE(s->slots); i++) { + for (i = 0; i < s->nr_slots; i++) { if (s->slots[i].memory_size == 0) { return &s->slots[i]; } @@ -141,7 +142,7 @@ static KVMSlot *kvm_lookup_matching_slot(KVMState *s, { int i; - for (i = 0; i < ARRAY_SIZE(s->slots); i++) { + for (i = 0; i < s->nr_slots; i++) { KVMSlot *mem = &s->slots[i]; if (start_addr == mem->start_addr && @@ -163,7 +164,7 @@ static KVMSlot *kvm_lookup_overlapping_slot(KVMState *s, KVMSlot *found = NULL; int i; - for (i = 0; i < ARRAY_SIZE(s->slots); i++) { + for (i = 0; i < s->nr_slots; i++) { KVMSlot *mem = &s->slots[i]; if (mem->memory_size == 0 || @@ -185,7 +186,7 @@ int kvm_physical_memory_addr_from_host(KVMState *s, void *ram, { int i; - for (i = 0; i < ARRAY_SIZE(s->slots); i++) { + for (i = 0; i < s->nr_slots; i++) { KVMSlot *mem = &s->slots[i]; if (ram >= mem->ram && ram < mem->ram + mem->memory_size) { @@ -357,7 +358,7 @@ static int kvm_set_migration_log(int enable) s->migration_log = enable; - for (i = 0; i < ARRAY_SIZE(s->slots); i++) { + for (i = 0; i < s->nr_slots; i++) { mem = &s->slots[i]; if (!mem->memory_size) { @@ -1383,9 +1384,6 @@ int kvm_init(void) #ifdef KVM_CAP_SET_GUEST_DEBUG QTAILQ_INIT(&s->kvm_sw_breakpoints); #endif - for (i = 0; i < ARRAY_SIZE(s->slots); i++) { - s->slots[i].slot = i; - } s->vmfd = -1; s->fd = qemu_open("/dev/kvm", O_RDWR); if (s->fd == -1) { @@ -1409,6 +1407,19 @@ int kvm_init(void) goto err; } + s->nr_slots = kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS); + + /* If unspecified, use the previous default value */ + if (!s->nr_slots) { + s->nr_slots = 32; + } + + s->slots = g_malloc0(s->nr_slots * sizeof(KVMSlot)); + + for (i = 0; i < s->nr_slots; i++) { + s->slots[i].slot = i; + } + /* check the vcpu limits */ soft_vcpus_limit = kvm_recommended_vcpus(s); hard_vcpus_limit = kvm_max_vcpus(s); @@ -1527,6 +1538,7 @@ err: if (s->fd != -1) { close(s->fd); } + g_free(s->slots); g_free(s); return ret;