From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58298) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VktDP-0000eu-Vn for qemu-devel@nongnu.org; Mon, 25 Nov 2013 05:16:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VktDG-00056r-QT for qemu-devel@nongnu.org; Mon, 25 Nov 2013 05:16:27 -0500 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:38272) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VktDG-00056S-Hz for qemu-devel@nongnu.org; Mon, 25 Nov 2013 05:16:18 -0500 Received: from /spool/local by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 25 Nov 2013 10:16:16 -0000 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 6825117D8059 for ; Mon, 25 Nov 2013 10:15:59 +0000 (GMT) Received: from d06av12.portsmouth.uk.ibm.com (d06av12.portsmouth.uk.ibm.com [9.149.37.247]) by b06cxnps4076.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rAPAG0SX61079732 for ; Mon, 25 Nov 2013 10:16:00 GMT Received: from d06av12.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av12.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rAPAGCcv017594 for ; Mon, 25 Nov 2013 03:16:12 -0700 Date: Mon, 25 Nov 2013 11:16:09 +0100 From: Thomas Huth Message-ID: <20131125111609.5eeaba97@oc7435384737.ibm.com> In-Reply-To: <20131122191154.16705.42189.stgit@bling.home> References: <20131122191154.16705.42189.stgit@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] kvm: Query KVM for available memory slots List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: pbonzini@redhat.com, kvm@vger.kernel.org, gleb@redhat.com, qemu-devel@nongnu.org On Fri, 22 Nov 2013 12:12:44 -0700 Alex Williamson wrote: > 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 */ I'd remove the "previous" in the comment here, because if you look at this code in a couple of years, nobody will remember what "previous" is refering to here. > + 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; Reviewed-by: Thomas Huth