[PATCH] KVM: PPC: Increase memslots to 512

[PATCH] KVM: PPC: Increase memslots to 512

[Thomas Huth]

Only using 32 memslots for KVM on powerpc is way too low, you can
nowadays hit this limit quite fast by adding a couple of PCI devices
and/or pluggable memory DIMMs to the guest.

x86 already increased the KVM_USER_MEM_SLOTS to 509, to satisfy 256
pluggable DIMM slots, 3 private slots and 253 slots for other things
like PCI devices (i.e. resulting in 256 + 3 + 253 = 512 slots in
total). We should do something similar for powerpc, and since we do
not use private slots here, we can set the value to 512 directly.

While we're at it, also remove the KVM_MEM_SLOTS_NUM definition
from the powerpc-specific header since this gets defined in the
generic kvm_host.h header anyway.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 arch/powerpc/include/asm/kvm_host.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 887c259..2c96a72 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -38,8 +38,7 @@
 
 #define KVM_MAX_VCPUS		NR_CPUS
 #define KVM_MAX_VCORES		NR_CPUS
-#define KVM_USER_MEM_SLOTS 32
-#define KVM_MEM_SLOTS_NUM KVM_USER_MEM_SLOTS
+#define KVM_USER_MEM_SLOTS	512
 
 #ifdef CONFIG_KVM_MMIO
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
-- 
1.8.3.1

[PATCH] KVM: PPC: Increase memslots to 512

[Thomas Huth]

Only using 32 memslots for KVM on powerpc is way too low, you can
nowadays hit this limit quite fast by adding a couple of PCI devices
and/or pluggable memory DIMMs to the guest.

x86 already increased the KVM_USER_MEM_SLOTS to 509, to satisfy 256
pluggable DIMM slots, 3 private slots and 253 slots for other things
like PCI devices (i.e. resulting in 256 + 3 + 253 = 512 slots in
total). We should do something similar for powerpc, and since we do
not use private slots here, we can set the value to 512 directly.

While we're at it, also remove the KVM_MEM_SLOTS_NUM definition
from the powerpc-specific header since this gets defined in the
generic kvm_host.h header anyway.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 arch/powerpc/include/asm/kvm_host.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 887c259..2c96a72 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -38,8 +38,7 @@
 
 #define KVM_MAX_VCPUS		NR_CPUS
 #define KVM_MAX_VCORES		NR_CPUS
-#define KVM_USER_MEM_SLOTS 32
-#define KVM_MEM_SLOTS_NUM KVM_USER_MEM_SLOTS
+#define KVM_USER_MEM_SLOTS	512
 
 #ifdef CONFIG_KVM_MMIO
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
-- 
1.8.3.1

Re: [PATCH] KVM: PPC: Increase memslots to 512

[Paul Mackerras]

On Wed, Dec 09, 2015 at 11:34:07AM +0100, Thomas Huth wrote:
> Only using 32 memslots for KVM on powerpc is way too low, you can
> nowadays hit this limit quite fast by adding a couple of PCI devices
> and/or pluggable memory DIMMs to the guest.
> 
> x86 already increased the KVM_USER_MEM_SLOTS to 509, to satisfy 256
> pluggable DIMM slots, 3 private slots and 253 slots for other things
> like PCI devices (i.e. resulting in 256 + 3 + 253 = 512 slots in
> total). We should do something similar for powerpc, and since we do
> not use private slots here, we can set the value to 512 directly.
> 
> While we're at it, also remove the KVM_MEM_SLOTS_NUM definition
> from the powerpc-specific header since this gets defined in the
> generic kvm_host.h header anyway.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Thanks, applied to my kvm-ppc-next branch.

Paul.

Re: [PATCH] KVM: PPC: Increase memslots to 512

[Paul Mackerras]

On Wed, Dec 09, 2015 at 11:34:07AM +0100, Thomas Huth wrote:
> Only using 32 memslots for KVM on powerpc is way too low, you can
> nowadays hit this limit quite fast by adding a couple of PCI devices
> and/or pluggable memory DIMMs to the guest.
> 
> x86 already increased the KVM_USER_MEM_SLOTS to 509, to satisfy 256
> pluggable DIMM slots, 3 private slots and 253 slots for other things
> like PCI devices (i.e. resulting in 256 + 3 + 253 = 512 slots in
> total). We should do something similar for powerpc, and since we do
> not use private slots here, we can set the value to 512 directly.
> 
> While we're at it, also remove the KVM_MEM_SLOTS_NUM definition
> from the powerpc-specific header since this gets defined in the
> generic kvm_host.h header anyway.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Thanks, applied to my kvm-ppc-next branch.

Paul.