Since adversising GICR_CTLR.{IC,CES} is directly observable from
a guest, we need to make it selectable from userspace.For that, bump the default GICD_IIDR revision and let userspace downgrade it to the previous default. For GICv2, the two distributor revisions are strictly equivalent. Signed-off-by: Marc Zyngier <[email protected]> --- arch/arm64/kvm/vgic/vgic-init.c | 7 ++++++- arch/arm64/kvm/vgic/vgic-mmio-v2.c | 18 +++++++++++++++--- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 23 +++++++++++++++++++++-- arch/arm64/kvm/vgic/vgic.h | 5 +++++ include/kvm/arm_vgic.h | 3 +++ 5 files changed, 50 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c index fc00304fe7d8..f84e04f334c6 100644 --- a/arch/arm64/kvm/vgic/vgic-init.c +++ b/arch/arm64/kvm/vgic/vgic-init.c @@ -319,7 +319,12 @@ int vgic_init(struct kvm *kvm) vgic_debug_init(kvm); - dist->implementation_rev = 2; + /* + * If userspace didn't set the GIC implementation revision, + * default to the latest and greatest. You know want it. + */ + if (!dist->implementation_rev) + dist->implementation_rev = KVM_VGIC_IMP_REV_LATEST; dist->initialized = true; out: diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v2.c b/arch/arm64/kvm/vgic/vgic-mmio-v2.c index 12e4c223e6b8..77a67e9d3d14 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v2.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v2.c @@ -73,9 +73,13 @@ static int vgic_mmio_uaccess_write_v2_misc(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len, unsigned long val) { + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; + u32 reg; + switch (addr & 0x0c) { case GIC_DIST_IIDR: - if (val != vgic_mmio_read_v2_misc(vcpu, addr, len)) + reg = vgic_mmio_read_v2_misc(vcpu, addr, len); + if ((reg ^ val) & ~GICD_IIDR_REVISION_MASK) return -EINVAL; /* @@ -87,8 +91,16 @@ static int vgic_mmio_uaccess_write_v2_misc(struct kvm_vcpu *vcpu, * migration from old kernels to new kernels with legacy * userspace. */ - vcpu->kvm->arch.vgic.v2_groups_user_writable = true; - return 0; + reg = FIELD_GET(GICD_IIDR_REVISION_MASK, reg); + switch (reg) { + case KVM_VGIC_IMP_REV_2: + case KVM_VGIC_IMP_REV_3: + vcpu->kvm->arch.vgic.v2_groups_user_writable = true; + dist->implementation_rev = reg; + return 0; + default: + return -EINVAL; + } } vgic_mmio_write_v2_misc(vcpu, addr, len, val); diff --git a/arch/arm64/kvm/vgic/vgic-mmio-v3.c b/arch/arm64/kvm/vgic/vgic-mmio-v3.c index 9824c773427d..f7aa7bcd6fb8 100644 --- a/arch/arm64/kvm/vgic/vgic-mmio-v3.c +++ b/arch/arm64/kvm/vgic/vgic-mmio-v3.c @@ -155,13 +155,27 @@ static int vgic_mmio_uaccess_write_v3_misc(struct kvm_vcpu *vcpu, unsigned long val) { struct vgic_dist *dist = &vcpu->kvm->arch.vgic; + u32 reg; switch (addr & 0x0c) { case GICD_TYPER2: - case GICD_IIDR: if (val != vgic_mmio_read_v3_misc(vcpu, addr, len)) return -EINVAL; return 0; + case GICD_IIDR: + reg = vgic_mmio_read_v3_misc(vcpu, addr, len); + if ((reg ^ val) & ~GICD_IIDR_REVISION_MASK) + return -EINVAL; + + reg = FIELD_GET(GICD_IIDR_REVISION_MASK, reg); + switch (reg) { + case KVM_VGIC_IMP_REV_2: + case KVM_VGIC_IMP_REV_3: + dist->implementation_rev = reg; + return 0; + default: + return -EINVAL; + } case GICD_CTLR: /* Not a GICv4.1? No HW SGIs */ if (!kvm_vgic_global_state.has_gicv4_1) @@ -232,8 +246,13 @@ static unsigned long vgic_mmio_read_v3r_ctlr(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len) { struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; + unsigned long val; + + val = atomic_read(&vgic_cpu->ctlr); + if (vgic_get_implementation_rev(vcpu) >= KVM_VGIC_IMP_REV_3) + val |= GICR_CTLR_IR | GICR_CTLR_CES; - return vgic_cpu->lpis_enabled ? GICR_CTLR_ENABLE_LPIS : 0; + return val; } static void vgic_mmio_write_v3r_ctlr(struct kvm_vcpu *vcpu, diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index 1d04a900f3e3..4c6bdd321faa 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -98,6 +98,11 @@ #define DEBUG_SPINLOCK_BUG_ON(p) #endif +static inline u32 vgic_get_implementation_rev(struct kvm_vcpu *vcpu) +{ + return vcpu->kvm->arch.vgic.implementation_rev; +} + /* Requires the irq_lock to be held by the caller. */ static inline bool irq_is_pending(struct vgic_irq *irq) { diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 401236f97cf2..2d8f2e90edc2 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -231,6 +231,9 @@ struct vgic_dist { /* Implementation revision as reported in the GICD_IIDR */ u32 implementation_rev; +#define KVM_VGIC_IMP_REV_2 2 /* GICv2 restorable groups */ +#define KVM_VGIC_IMP_REV_3 3 /* GICv3 GICR_CTLR.{IW,CES,RWP} */ +#define KVM_VGIC_IMP_REV_LATEST KVM_VGIC_IMP_REV_3 /* Userspace can write to GICv2 IGROUPR */ bool v2_groups_user_writable; -- 2.34.1 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
