On Mon, Nov 10, 2014 at 12:26:28PM +0000, Andre Przywara wrote:

Hej Christoffer,

On 07/11/14 16:15, Christoffer Dall wrote:

quoted

On Fri, Oct 31, 2014 at 05:26:54PM +0000, Andre Przywara wrote:

quoted

With everything in place we allow userland to request the kernel
using a virtual GICv3 in the guest, which finally lifts the 8 vCPU
limit for a guest.

You're actually not explicitly allowing this in this patch, you're
implicitly allowing it because init would fail without the vgic
distributor base address being set already.

Either re-arrange your patches or fix the commit message.

The latter ;-)

quoted

quoted

Also we provide the necessary support for guests setting the memory
addresses for the virtual distributor and redistributors.
This requires some userland code to make use of that feature and
explicitly ask for a virtual GICv3.

You need to add documentation for this new device type and the userspace
ABI.

Will do.

quoted

quoted

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 arch/arm64/include/uapi/asm/kvm.h |    7 ++++++
 include/kvm/arm_vgic.h            |    4 ++--
 virt/kvm/arm/vgic-v3-emul.c       |    3 +++
 virt/kvm/arm/vgic.c               |   46 ++++++++++++++++++++++++++-----------
 4 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 8e38878..2ed873a 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h

@@ -78,6 +78,13 @@ struct kvm_regs {
 #define KVM_VGIC_V2_DIST_SIZE		0x1000
 #define KVM_VGIC_V2_CPU_SIZE		0x2000
 
+/* Supported VGICv3 address types  */
+#define KVM_VGIC_V3_ADDR_TYPE_DIST	2
+#define KVM_VGIC_V3_ADDR_TYPE_REDIST	3
+
+#define KVM_VGIC_V3_DIST_SIZE		SZ_64K
+#define KVM_VGIC_V3_REDIST_SIZE		(2 * SZ_64K)
+
 #define KVM_ARM_VCPU_POWER_OFF		0 /* CPU is started in OFF state */
 #define KVM_ARM_VCPU_EL1_32BIT		1 /* CPU running a 32bit VM */
 #define KVM_ARM_VCPU_PSCI_0_2		2 /* CPU uses PSCI v0.2 */

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index c303083..e2e432c 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h

@@ -35,8 +35,8 @@
 #define VGIC_MAX_IRQS		1024
 
 /* Sanity checks... */
-#if (KVM_MAX_VCPUS > 8)
-#error	Invalid number of CPU interfaces
+#if (KVM_MAX_VCPUS > 255)
+#error Too many KVM VCPUs, the VGIC only supports up to 255 VCPUs for now

what happens now if you add more vcpus after having created a GICv2 with
8 vcpus?

On adding a VCPU we check the number of allowed VCPUs for this
particular guest (see arch/arm/kvm/arm.c:kvm_arch_vcpu_create() in patch
09/19). On creating a virtual GICv2 we set the limit to 8, so any
KVM_VCPU_CREATE afterwards will fail.

But indeed I found other issues in this sequence of VCPU/VGIC init,
which dissolved "magically" by the rework around (or actually the drop
of) init_emul() and friends.

I see, thanks.
-Christoffer