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Re: [Qemu-devel] [PATCH] kvm: Detect number of available memory slots fr
From: |
Gleb Natapov |
Subject: |
Re: [Qemu-devel] [PATCH] kvm: Detect number of available memory slots from the host kernel |
Date: |
Sun, 9 Dec 2012 16:20:43 +0200 |
On Fri, Dec 07, 2012 at 12:46:10PM -0700, Alex Williamson wrote:
> The kernel already exposes an interface for this, x86 returns a proper
> value and for the rest we can default to the defacto standard of 32.
> The primary motivation for this is to support more PCI assigned
> devices, both through pci-assign and vfio-pci.
>
> Signed-off-by: Alex Williamson <address@hidden>
> ---
> kvm-all.c | 27 ++++++++++++++++++---------
> 1 file changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 8e9a8d8..34d97f3 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -71,7 +71,8 @@ typedef struct kvm_dirty_log KVMDirtyLog;
>
> struct KVMState
> {
> - KVMSlot slots[32];
> + KVMSlot *slots;
> + int num_slots;
> int fd;
> int vmfd;
> int coalesced_mmio;
> @@ -120,7 +121,7 @@ static KVMSlot *kvm_alloc_slot(KVMState *s)
> {
> int i;
>
> - for (i = 0; i < ARRAY_SIZE(s->slots); i++) {
> + for (i = 0; i < s->num_slots; i++) {
> if (s->slots[i].memory_size == 0) {
> return &s->slots[i];
> }
> @@ -136,7 +137,7 @@ static KVMSlot *kvm_lookup_matching_slot(KVMState *s,
> {
> int i;
>
> - for (i = 0; i < ARRAY_SIZE(s->slots); i++) {
> + for (i = 0; i < s->num_slots; i++) {
> KVMSlot *mem = &s->slots[i];
>
> if (start_addr == mem->start_addr &&
> @@ -158,7 +159,7 @@ 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->num_slots; i++) {
> KVMSlot *mem = &s->slots[i];
>
> if (mem->memory_size == 0 ||
> @@ -180,7 +181,7 @@ 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->num_slots; i++) {
> KVMSlot *mem = &s->slots[i];
>
> if (ram >= mem->ram && ram < mem->ram + mem->memory_size) {
> @@ -340,7 +341,7 @@ 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->num_slots; i++) {
> mem = &s->slots[i];
>
> if (!mem->memory_size) {
> @@ -1268,9 +1269,6 @@ 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) {
> @@ -1324,6 +1322,16 @@ int kvm_init(void)
> goto err;
> }
>
> + s->num_slots = kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS);
> + if (s->num_slots <= 0) {
kvm_check_extension() never returns negative value, so !s->num_slots
check is enough. Other than that minor nit looks OK.
> + s->num_slots = 32;
> + }
> + s->slots = g_malloc0(s->num_slots * sizeof(*s->slots));
> +
> + for (i = 0; i < s->num_slots; i++) {
> + s->slots[i].slot = i;
> + }
> +
> s->coalesced_mmio = kvm_check_extension(s, KVM_CAP_COALESCED_MMIO);
>
> s->broken_set_mem_region = 1;
> @@ -1393,6 +1401,7 @@ err:
> if (s->fd != -1) {
> close(s->fd);
> }
> + g_free(s->slots);
> g_free(s);
>
> return ret;
--
Gleb.