KVM: arm64: vgic: Handle ITS related GICv3 redistributor registers

In the GICv3 redistributor there are the PENDBASER and PROPBASER
registers which we did not emulate so far, as they only make sense
when having an ITS. In preparation for that emulate those MMIO
accesses by storing the 64-bit data written into it into a variable
which we later read in the ITS emulation.
We also sanitise the registers, making sure RES0 regions are respected
and checking for valid memory attributes.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

3 files changed, 168 insertions, 4 deletions

diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index bfcafbd8fa02..278bfbb36ef9 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -29,6 +29,19 @@ static unsigned long extract_bytes(unsigned long data, unsigned int offset,
 	return (data >> (offset * 8)) & GENMASK_ULL(num * 8 - 1, 0);
 }
 
+/* allows updates of any half of a 64-bit register (or the whole thing) */
+static u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
+			    unsigned long val)
+{
+	int lower = (offset & 4) * 8;
+	int upper = lower + 8 * len - 1;
+
+	reg &= ~GENMASK_ULL(upper, lower);
+	val &= GENMASK_ULL(len * 8 - 1, 0);
+
+	return reg | ((u64)val << lower);
+}
+
 static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 					    gpa_t addr, unsigned int len)
 {
@@ -152,6 +165,142 @@ static unsigned long vgic_mmio_read_v3_idregs(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+/* We want to avoid outer shareable. */
+u64 vgic_sanitise_shareability(u64 field)
+{
+	switch (field) {
+	case GIC_BASER_OuterShareable:
+		return GIC_BASER_InnerShareable;
+	default:
+		return field;
+	}
+}
+
+/* Avoid any inner non-cacheable mapping. */
+u64 vgic_sanitise_inner_cacheability(u64 field)
+{
+	switch (field) {
+	case GIC_BASER_CACHE_nCnB:
+	case GIC_BASER_CACHE_nC:
+		return GIC_BASER_CACHE_RaWb;
+	default:
+		return field;
+	}
+}
+
+/* Non-cacheable or same-as-inner are OK. */
+u64 vgic_sanitise_outer_cacheability(u64 field)
+{
+	switch (field) {
+	case GIC_BASER_CACHE_SameAsInner:
+	case GIC_BASER_CACHE_nC:
+		return field;
+	default:
+		return GIC_BASER_CACHE_nC;
+	}
+}
+
+u64 vgic_sanitise_field(u64 reg, u64 field_mask, int field_shift,
+			u64 (*sanitise_fn)(u64))
+{
+	u64 field = (reg & field_mask) >> field_shift;
+
+	field = sanitise_fn(field) << field_shift;
+	return (reg & ~field_mask) | field;
+}
+
+#define PROPBASER_RES0_MASK						\
+	(GENMASK_ULL(63, 59) | GENMASK_ULL(55, 52) | GENMASK_ULL(6, 5))
+#define PENDBASER_RES0_MASK						\
+	(BIT_ULL(63) | GENMASK_ULL(61, 59) | GENMASK_ULL(55, 52) |	\
+	 GENMASK_ULL(15, 12) | GENMASK_ULL(6, 0))
+
+static u64 vgic_sanitise_pendbaser(u64 reg)
+{
+	reg = vgic_sanitise_field(reg, GICR_PENDBASER_SHAREABILITY_MASK,
+				  GICR_PENDBASER_SHAREABILITY_SHIFT,
+				  vgic_sanitise_shareability);
+	reg = vgic_sanitise_field(reg, GICR_PENDBASER_INNER_CACHEABILITY_MASK,
+				  GICR_PENDBASER_INNER_CACHEABILITY_SHIFT,
+				  vgic_sanitise_inner_cacheability);
+	reg = vgic_sanitise_field(reg, GICR_PENDBASER_OUTER_CACHEABILITY_MASK,
+				  GICR_PENDBASER_OUTER_CACHEABILITY_SHIFT,
+				  vgic_sanitise_outer_cacheability);
+
+	reg &= ~PENDBASER_RES0_MASK;
+	reg &= ~GENMASK_ULL(51, 48);
+
+	return reg;
+}
+
+static u64 vgic_sanitise_propbaser(u64 reg)
+{
+	reg = vgic_sanitise_field(reg, GICR_PROPBASER_SHAREABILITY_MASK,
+				  GICR_PROPBASER_SHAREABILITY_SHIFT,
+				  vgic_sanitise_shareability);
+	reg = vgic_sanitise_field(reg, GICR_PROPBASER_INNER_CACHEABILITY_MASK,
+				  GICR_PROPBASER_INNER_CACHEABILITY_SHIFT,
+				  vgic_sanitise_inner_cacheability);
+	reg = vgic_sanitise_field(reg, GICR_PROPBASER_OUTER_CACHEABILITY_MASK,
+				  GICR_PROPBASER_OUTER_CACHEABILITY_SHIFT,
+				  vgic_sanitise_outer_cacheability);
+
+	reg &= ~PROPBASER_RES0_MASK;
+	reg &= ~GENMASK_ULL(51, 48);
+	return reg;
+}
+
+static unsigned long vgic_mmio_read_propbase(struct kvm_vcpu *vcpu,
+					     gpa_t addr, unsigned int len)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	return extract_bytes(dist->propbaser, addr & 7, len);
+}
+
+static void vgic_mmio_write_propbase(struct kvm_vcpu *vcpu,
+				     gpa_t addr, unsigned int len,
+				     unsigned long val)
+{
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	u64 propbaser = dist->propbaser;
+
+	/* Storing a value with LPIs already enabled is undefined */
+	if (vgic_cpu->lpis_enabled)
+		return;
+
+	propbaser = update_64bit_reg(propbaser, addr & 4, len, val);
+	propbaser = vgic_sanitise_propbaser(propbaser);
+
+	dist->propbaser = propbaser;
+}
+
+static unsigned long vgic_mmio_read_pendbase(struct kvm_vcpu *vcpu,
+					     gpa_t addr, unsigned int len)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+
+	return extract_bytes(vgic_cpu->pendbaser, addr & 7, len);
+}
+
+static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu,
+				     gpa_t addr, unsigned int len,
+				     unsigned long val)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	u64 pendbaser = vgic_cpu->pendbaser;
+
+	/* Storing a value with LPIs already enabled is undefined */
+	if (vgic_cpu->lpis_enabled)
+		return;
+
+	pendbaser = update_64bit_reg(pendbaser, addr & 4, len, val);
+	pendbaser = vgic_sanitise_pendbaser(pendbaser);
+
+	vgic_cpu->pendbaser = pendbaser;
+}
+
 /*
  * The GICv3 per-IRQ registers are split to control PPIs and SGIs in the
  * redistributors, while SPIs are covered by registers in the distributor
@@ -232,10 +381,10 @@ static const struct vgic_register_region vgic_v3_rdbase_registers[] = {
 		vgic_mmio_read_v3r_typer, vgic_mmio_write_wi, 8,
 		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICR_PROPBASER,
-		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
+		vgic_mmio_read_propbase, vgic_mmio_write_propbase, 8,
 		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICR_PENDBASER,
-		vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
+		vgic_mmio_read_pendbase, vgic_mmio_write_pendbase, 8,
 		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICR_IDREGS,
 		vgic_mmio_read_v3_idregs, vgic_mmio_write_wi, 48,
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 850901482aec..71aa39d4cfdf 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -147,4 +147,12 @@ unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
 
 unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);
 
+#ifdef CONFIG_KVM_ARM_VGIC_V3
+u64 vgic_sanitise_outer_cacheability(u64 reg);
+u64 vgic_sanitise_inner_cacheability(u64 reg);
+u64 vgic_sanitise_shareability(u64 reg);
+u64 vgic_sanitise_field(u64 reg, u64 field_mask, int field_shift,
+			u64 (*sanitise_fn)(u64));
+#endif
+
 #endif
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index f0ac0642303c..6f8f31f910e7 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -191,6 +191,11 @@ void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 	vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;
 }
 
+#define INITIAL_PENDBASER_VALUE						  \
+	(GIC_BASER_CACHEABILITY(GICR_PENDBASER, INNER, RaWb)		| \
+	GIC_BASER_CACHEABILITY(GICR_PENDBASER, OUTER, SameAsInner)	| \
+	GIC_BASER_SHAREABILITY(GICR_PENDBASER, InnerShareable))
+
 void vgic_v3_enable(struct kvm_vcpu *vcpu)
 {
 	struct vgic_v3_cpu_if *vgic_v3 = &vcpu->arch.vgic_cpu.vgic_v3;
@@ -208,10 +213,12 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu)
 	 * way, so we force SRE to 1 to demonstrate this to the guest.
 	 * This goes with the spec allowing the value to be RAO/WI.
 	 */
-	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
+	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 		vgic_v3->vgic_sre = ICC_SRE_EL1_SRE;
-	else
+		vcpu->arch.vgic_cpu.pendbaser = INITIAL_PENDBASER_VALUE;
+	} else {
 		vgic_v3->vgic_sre = 0;
+	}
 
 	/* Get the show on the road... */
 	vgic_v3->vgic_hcr = ICH_HCR_EN;