GIC CPU interfaces versions predating GIC v4.1 were not built to
accommodate vINTID within the vSGI range; as reported in the GIC
specifications (8.2 "Changes to the CPU interface"), it is
CONSTRAINED UNPREDICTABLE to deliver a vSGI to a PE with
ID_AA64PFR0_EL1.GIC < b0011.
Check the GIC CPUIF version by reading the SYS_ID_AA64_PFR0_EL1.
Disable vSGIs if a CPUIF version < 4.1 is detected to prevent using
vSGIs on systems where they may misbehave.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/kvm/vgic/vgic-mmio-v3.c | 4 ++--
drivers/irqchip/irq-gic-v4.c | 27 +++++++++++++++++++++++++--
include/linux/irqchip/arm-gic-v4.h | 2 ++
3 files changed, 29 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
index 15a6c98ee92f..2f1b156021a6 100644
--- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c
@@ -86,7 +86,7 @@ static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
}
break;
case GICD_TYPER2:
- if (kvm_vgic_global_state.has_gicv4_1)
+ if (kvm_vgic_global_state.has_gicv4_1 && gic_cpuif_has_vsgi())
value = GICD_TYPER2_nASSGIcap;
break;
case GICD_IIDR:
@@ -119,7 +119,7 @@ static void vgic_mmio_write_v3_misc(struct kvm_vcpu *vcpu,
dist->enabled = val & GICD_CTLR_ENABLE_SS_G1;
/* Not a GICv4.1? No HW SGIs */
- if (!kvm_vgic_global_state.has_gicv4_1)
+ if (!kvm_vgic_global_state.has_gicv4_1 || !gic_cpuif_has_vsgi())
val &= ~GICD_CTLR_nASSGIreq;
/* Dist stays enabled? nASSGIreq is RO */
diff --git a/drivers/irqchip/irq-gic-v4.c b/drivers/irqchip/irq-gic-v4.c
index 5d1dc9915272..4ea71b28f9f5 100644
--- a/drivers/irqchip/irq-gic-v4.c
+++ b/drivers/irqchip/irq-gic-v4.c
@@ -87,17 +87,40 @@ static struct irq_domain *gic_domain;
static const struct irq_domain_ops *vpe_domain_ops;
static const struct irq_domain_ops *sgi_domain_ops;
+#ifdef CONFIG_ARM64
+#include <asm/cpufeature.h>
+
+bool gic_cpuif_has_vsgi(void)
+{
+ unsigned long fld, reg = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
+
+ fld = cpuid_feature_extract_unsigned_field(reg, ID_AA64PFR0_GIC_SHIFT);
+
+ return fld >= 0x3;
+}
+#else
+bool gic_cpuif_has_vsgi(void)
+{
+ return false;
+}
+#endif
+
static bool has_v4_1(void)
{
return !!sgi_domain_ops;
}
+static bool has_v4_1_sgi(void)
+{
+ return has_v4_1() && gic_cpuif_has_vsgi();
+}
+
static int its_alloc_vcpu_sgis(struct its_vpe *vpe, int idx)
{
char *name;
int sgi_base;
- if (!has_v4_1())
+ if (!has_v4_1_sgi())
return 0;
name = kasprintf(GFP_KERNEL, "GICv4-sgi-%d", task_pid_nr(current));
@@ -182,7 +205,7 @@ static void its_free_sgi_irqs(struct its_vm *vm)
{
int i;
- if (!has_v4_1())
+ if (!has_v4_1_sgi())
return;
for (i = 0; i < vm->nr_vpes; i++) {
diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h
index 943c3411ca10..2c63375bbd43 100644
--- a/include/linux/irqchip/arm-gic-v4.h
+++ b/include/linux/irqchip/arm-gic-v4.h
@@ -145,4 +145,6 @@ int its_init_v4(struct irq_domain *domain,
const struct irq_domain_ops *vpe_ops,
const struct irq_domain_ops *sgi_ops);
+bool gic_cpuif_has_vsgi(void);
+
#endif
--
2.29.1
