On Thu, May 12, 2016 at 07:52:38PM +0100, Andre Przywara wrote:

Hi,

On 12/05/16 19:47, Christoffer Dall wrote:

quoted

On Fri, May 06, 2016 at 11:46:00AM +0100, Andre Przywara wrote:

quoted

Using the VMCR accessors we provide access to GIC CPU interface state
to userland by wiring it up to the existing userland interface.
[Marc: move and make VMCR accessors static, streamline MMIO handlers]

does this mean Marc did this and serves as credit or is it a lost
reminder?

It was meant as credit. I thought that is the usual annotation for this?

I'm not sure if that's the usual way, I read it as a reminder, but it's
not too important.  Mostly wanting to make sure we're not forgetting
some todo item.

quoted

quoted

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <redacted>
---
Changelog v2 .. v3:
- total rework, moving into vgic-mmio-v2.c
- move vmcr accessor wrapper functions into this file
- use the register description table for CPU i/f registers as well
- add RAZ/WI handling for the active priority registers
- streamline MMIO handler functions

 virt/kvm/arm/vgic/vgic-kvm-device.c |   2 +-
 virt/kvm/arm/vgic/vgic-mmio-v2.c    | 104 ++++++++++++++++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic.h            |   2 +
 3 files changed, 107 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
index bb33af8..2122ff2 100644
--- a/virt/kvm/arm/vgic/vgic-kvm-device.c
+++ b/virt/kvm/arm/vgic/vgic-kvm-device.c

@@ -300,7 +300,7 @@ static int vgic_attr_regs_access(struct kvm_device *dev,
 
 	switch (attr->group) {
 	case KVM_DEV_ARM_VGIC_GRP_CPU_REGS:
-		ret = -EINVAL;
+		ret = vgic_v2_cpuif_uaccess(vcpu, is_write, addr, reg);
 		break;
 	case KVM_DEV_ARM_VGIC_GRP_DIST_REGS:
 		ret = vgic_v2_dist_uaccess(vcpu, is_write, addr, reg);

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index c453e6f..0060539 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c

@@ -206,6 +206,84 @@ static void vgic_mmio_write_sgipends(struct kvm_vcpu *vcpu,
 	}
 }
 
+static void vgic_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
+{
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_set_vmcr(vcpu, vmcr);
+	else
+		vgic_v3_set_vmcr(vcpu, vmcr);
+}
+
+static void vgic_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
+{
+	if (kvm_vgic_global_state.type == VGIC_V2)
+		vgic_v2_get_vmcr(vcpu, vmcr);
+	else
+		vgic_v3_get_vmcr(vcpu, vmcr);
+}
+
+#define GICC_ARCH_VERSION_V2	0x2
+
+/* These are for userland accesses only, there is no guest-facing emulation. */
+static unsigned long vgic_mmio_read_vcpuif(struct kvm_vcpu *vcpu,
+					   gpa_t addr, unsigned int len)
+{
+	struct vgic_vmcr vmcr;
+	u32 val;
+
+	vgic_get_vmcr(vcpu, &vmcr);
+
+	switch (addr & 0xff) {
+	case GIC_CPU_CTRL:
+		val = vmcr.ctlr;
+		break;
+	case GIC_CPU_PRIMASK:
+		val = vmcr.pmr;
+		break;
+	case GIC_CPU_BINPOINT:
+		val = vmcr.bpr;
+		break;
+	case GIC_CPU_ALIAS_BINPOINT:
+		val = vmcr.abpr;
+		break;
+	case GIC_CPU_IDENT:
+		val = ((PRODUCT_ID_KVM << 20) |
+		       (GICC_ARCH_VERSION_V2 << 16) |
+		       IMPLEMENTER_ARM);
+		break;
+	default:
+		return 0;
+	}
+
+	return extract_bytes(val, addr & 3, len);

I don't think we allow anything than a full 32-bit aligned accesses
from userspace - we shouldn't at least.

Indeed - I think userland was always 32-bit only. And since last night
we even enforce this. So potentially there are more extract_bytes()
calls that can go.

Right.

-Christoffer