* [Qemu-devel] [PATCH] kvm: Query KVM for available memory slots
@ 2013-11-22 19:12 Alex Williamson
2013-11-25 10:16 ` Thomas Huth
0 siblings, 1 reply; 3+ messages in thread
From: Alex Williamson @ 2013-11-22 19:12 UTC (permalink / raw)
To: pbonzini, gleb, kvm; +Cc: qemu-devel
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 <alex.williamson@redhat.com>
---
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;
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] kvm: Query KVM for available memory slots
2013-11-22 19:12 [Qemu-devel] [PATCH] kvm: Query KVM for available memory slots Alex Williamson
@ 2013-11-25 10:16 ` Thomas Huth
2013-11-25 10:41 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Huth @ 2013-11-25 10:16 UTC (permalink / raw)
To: Alex Williamson; +Cc: pbonzini, kvm, gleb, qemu-devel
On Fri, 22 Nov 2013 12:12:44 -0700
Alex Williamson <alex.williamson@redhat.com> 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 <alex.williamson@redhat.com>
> ---
> 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 <thuth@linux.vnet.ibm.com>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] kvm: Query KVM for available memory slots
2013-11-25 10:16 ` Thomas Huth
@ 2013-11-25 10:41 ` Paolo Bonzini
0 siblings, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2013-11-25 10:41 UTC (permalink / raw)
To: Thomas Huth; +Cc: Alex Williamson, gleb, kvm, qemu-devel
Il 25/11/2013 11:16, Thomas Huth ha scritto:
> On Fri, 22 Nov 2013 12:12:44 -0700
> Alex Williamson <alex.williamson@redhat.com> 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 <alex.williamson@redhat.com>
>> ---
>> 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 <thuth@linux.vnet.ibm.com>
Thanks, applied to uq/master with your suggested change.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-11-25 10:16 ` Thomas Huth
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