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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] ARM: new VGIC: Add GICv2 world switch backend
commit ec3e023f12a6bb48b3864abccb5bde9de24e6c75
Author: Andre Przywara <andre.przywara@xxxxxxxxxx>
AuthorDate: Wed Feb 7 12:33:16 2018 +0000
Commit: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Wed Mar 28 10:52:50 2018 -0700
ARM: new VGIC: Add GICv2 world switch backend
Processing maintenance interrupts and accessing the list registers
are dependent on the host's GIC version.
Introduce vgic-v2.c to contain GICv2 specific functions.
Implement the GICv2 specific code for syncing the emulation state
into the VGIC registers.
This also adds the hook to let Xen setup the host GIC addresses.
This is based on Linux commit 140b086dd197, written by Marc Zyngier.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
xen/arch/arm/vgic/vgic-v2.c | 259 ++++++++++++++++++++++++++++++++++++++++++++
xen/arch/arm/vgic/vgic.c | 6 +
xen/arch/arm/vgic/vgic.h | 9 ++
3 files changed, 274 insertions(+)
diff --git a/xen/arch/arm/vgic/vgic-v2.c b/xen/arch/arm/vgic/vgic-v2.c
new file mode 100644
index 0000000000..4ad018e904
--- /dev/null
+++ b/xen/arch/arm/vgic/vgic-v2.c
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2015, 2016 ARM Ltd.
+ * Imported from Linux ("new" KVM VGIC) and heavily adapted to Xen.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <asm/new_vgic.h>
+#include <asm/bug.h>
+#include <asm/gic.h>
+#include <xen/sched.h>
+#include <xen/sizes.h>
+
+#include "vgic.h"
+
+static struct {
+ bool enabled;
+ paddr_t dbase; /* Distributor interface address */
+ paddr_t cbase; /* CPU interface address & size */
+ paddr_t csize;
+ paddr_t vbase; /* Virtual CPU interface address */
+
+ /* Offset to add to get an 8kB contiguous region if GIC is aliased */
+ uint32_t aliased_offset;
+} gic_v2_hw_data;
+
+void vgic_v2_setup_hw(paddr_t dbase, paddr_t cbase, paddr_t csize,
+ paddr_t vbase, uint32_t aliased_offset)
+{
+ gic_v2_hw_data.enabled = true;
+ gic_v2_hw_data.dbase = dbase;
+ gic_v2_hw_data.cbase = cbase;
+ gic_v2_hw_data.csize = csize;
+ gic_v2_hw_data.vbase = vbase;
+ gic_v2_hw_data.aliased_offset = aliased_offset;
+
+ printk("Using the new VGIC implementation.\n");
+}
+
+/*
+ * transfer the content of the LRs back into the corresponding ap_list:
+ * - active bit is transferred as is
+ * - pending bit is
+ * - transferred as is in case of edge sensitive IRQs
+ * - set to the line-level (resample time) for level sensitive IRQs
+ */
+void vgic_v2_fold_lr_state(struct vcpu *vcpu)
+{
+ struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic;
+ unsigned int used_lrs = vcpu->arch.vgic.used_lrs;
+ unsigned long flags;
+ unsigned int lr;
+
+ if ( !used_lrs ) /* No LRs used, so nothing to sync back here. */
+ return;
+
+ gic_hw_ops->update_hcr_status(GICH_HCR_UIE, false);
+
+ for ( lr = 0; lr < used_lrs; lr++ )
+ {
+ struct gic_lr lr_val;
+ uint32_t intid;
+ struct vgic_irq *irq;
+ struct irq_desc *desc = NULL;
+
+ gic_hw_ops->read_lr(lr, &lr_val);
+
+ /*
+ * TODO: Possible optimization to avoid reading LRs:
+ * Read the ELRSR to find out which of our LRs have been cleared
+ * by the guest. We just need to know the IRQ number for those, which
+ * we could save in an array when populating the LRs.
+ * This trades one MMIO access (ELRSR) for possibly more than one
(LRs),
+ * but requires some more code to save the IRQ number and to handle
+ * those finished IRQs according to the algorithm below.
+ * We need some numbers to justify this: chances are that we don't
+ * have many LRs in use most of the time, so we might not save much.
+ */
+ gic_hw_ops->clear_lr(lr);
+
+ intid = lr_val.virq;
+ irq = vgic_get_irq(vcpu->domain, vcpu, intid);
+
+ local_irq_save(flags);
+
+ /*
+ * We check this here without taking the lock, because the locking
+ * order forces us to do so. irq->hw is a "write-once" member, so
+ * whenever we read true, the associated hardware IRQ will not go
+ * away anymore.
+ * TODO: rework this if possible, either by using the desc pointer
+ * directly in struct vgic_irq or by changing the locking order.
+ * Especially if we ever drop the assumption above.
+ */
+ if ( irq->hw )
+ {
+ desc = irq_to_desc(irq->hwintid);
+ spin_lock(&desc->lock);
+ }
+
+ spin_lock(&irq->irq_lock);
+
+ /*
+ * If a hardware mapped IRQ has been handled for good, we need to
+ * clear the _IRQ_INPROGRESS bit to allow handling of new IRQs.
+ *
+ * TODO: This is probably racy, but is so already in the existing
+ * VGIC. A fix does not seem to be trivial.
+ */
+ if ( irq->hw && !lr_val.active && !lr_val.pending )
+ clear_bit(_IRQ_INPROGRESS, &desc->status);
+
+ /* Always preserve the active bit */
+ irq->active = lr_val.active;
+
+ /* Edge is the only case where we preserve the pending bit */
+ if ( irq->config == VGIC_CONFIG_EDGE && lr_val.pending )
+ {
+ irq->pending_latch = true;
+
+ if ( vgic_irq_is_sgi(intid) )
+ irq->source |= (1U << lr_val.virt.source);
+ }
+
+ /* Clear soft pending state when level irqs have been acked. */
+ if ( irq->config == VGIC_CONFIG_LEVEL && !lr_val.pending )
+ irq->pending_latch = false;
+
+ /*
+ * Level-triggered mapped IRQs are special because we only
+ * observe rising edges as input to the VGIC.
+ *
+ * If the guest never acked the interrupt we have to sample
+ * the physical line and set the line level, because the
+ * device state could have changed or we simply need to
+ * process the still pending interrupt later.
+ *
+ * If this causes us to lower the level, we have to also clear
+ * the physical active state, since we will otherwise never be
+ * told when the interrupt becomes asserted again.
+ */
+ if ( vgic_irq_is_mapped_level(irq) && lr_val.pending )
+ {
+ ASSERT(irq->hwintid >= VGIC_NR_PRIVATE_IRQS);
+
+ irq->line_level = gic_read_pending_state(desc);
+
+ if ( !irq->line_level )
+ gic_set_active_state(desc, false);
+ }
+
+ spin_unlock(&irq->irq_lock);
+ if ( desc )
+ spin_unlock(&desc->lock);
+ local_irq_restore(flags);
+
+ vgic_put_irq(vcpu->domain, irq);
+ }
+
+ gic_hw_ops->update_hcr_status(GICH_HCR_EN, false);
+ vgic_cpu->used_lrs = 0;
+}
+
+/**
+ * vgic_v2_populate_lr() - Populates an LR with the state of a given IRQ.
+ * @vcpu: The VCPU which the given @irq belongs to.
+ * @irq: The IRQ to convert into an LR. The irq_lock must be held already.
+ * @lr: The LR number to transfer the state into.
+ *
+ * This moves a virtual IRQ, represented by its vgic_irq, into a list register.
+ * Apart from translating the logical state into the LR bitfields, it also
+ * changes some state in the vgic_irq.
+ * For an edge sensitive IRQ the pending state is cleared in struct vgic_irq,
+ * for a level sensitive IRQ the pending state value is unchanged, as it is
+ * dictated directly by the input line level.
+ *
+ * If @irq describes an SGI with multiple sources, we choose the
+ * lowest-numbered source VCPU and clear that bit in the source bitmap.
+ *
+ * The irq_lock must be held by the caller.
+ */
+void vgic_v2_populate_lr(struct vcpu *vcpu, struct vgic_irq *irq, int lr)
+{
+ struct gic_lr lr_val = {0};
+
+ lr_val.virq = irq->intid;
+
+ if ( irq_is_pending(irq) )
+ {
+ lr_val.pending = true;
+
+ if ( irq->config == VGIC_CONFIG_EDGE )
+ irq->pending_latch = false;
+
+ if ( vgic_irq_is_sgi(irq->intid) )
+ {
+ uint32_t src = ffs(irq->source);
+
+ BUG_ON(!src);
+ lr_val.virt.source = (src - 1);
+ irq->source &= ~(1 << (src - 1));
+ if ( irq->source )
+ irq->pending_latch = true;
+ }
+ }
+
+ lr_val.active = irq->active;
+
+ if ( irq->hw )
+ {
+ lr_val.hw_status = true;
+ lr_val.hw.pirq = irq->hwintid;
+ /*
+ * Never set pending+active on a HW interrupt, as the
+ * pending state is kept at the physical distributor
+ * level.
+ */
+ if ( irq->active && irq_is_pending(irq) )
+ lr_val.pending = false;
+ }
+ else
+ {
+ if ( irq->config == VGIC_CONFIG_LEVEL )
+ lr_val.virt.eoi = true;
+ }
+
+ /*
+ * Level-triggered mapped IRQs are special because we only observe
+ * rising edges as input to the VGIC. We therefore lower the line
+ * level here, so that we can take new virtual IRQs. See
+ * vgic_v2_fold_lr_state for more info.
+ */
+ if ( vgic_irq_is_mapped_level(irq) && lr_val.pending )
+ irq->line_level = false;
+
+ /* The GICv2 LR only holds five bits of priority. */
+ lr_val.priority = irq->priority >> 3;
+
+ gic_hw_ops->write_lr(lr, &lr_val);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/vgic/vgic.c b/xen/arch/arm/vgic/vgic.c
index 401b10c323..e938d0033d 100644
--- a/xen/arch/arm/vgic/vgic.c
+++ b/xen/arch/arm/vgic/vgic.c
@@ -520,6 +520,7 @@ retry:
static void vgic_fold_lr_state(struct vcpu *vcpu)
{
+ vgic_v2_fold_lr_state(vcpu);
}
/* Requires the irq_lock to be held. */
@@ -527,6 +528,8 @@ static void vgic_populate_lr(struct vcpu *vcpu,
struct vgic_irq *irq, int lr)
{
ASSERT(spin_is_locked(&irq->irq_lock));
+
+ vgic_v2_populate_lr(vcpu, irq, lr);
}
static void vgic_set_underflow(struct vcpu *vcpu)
@@ -633,7 +636,10 @@ void vgic_sync_to_lrs(void)
spin_lock(¤t->arch.vgic.ap_list_lock);
vgic_flush_lr_state(current);
spin_unlock(¤t->arch.vgic.ap_list_lock);
+
+ gic_hw_ops->update_hcr_status(GICH_HCR_EN, 1);
}
+
/*
* Local variables:
* mode: C
diff --git a/xen/arch/arm/vgic/vgic.h b/xen/arch/arm/vgic/vgic.h
index 1547478518..e2b6d51e47 100644
--- a/xen/arch/arm/vgic/vgic.h
+++ b/xen/arch/arm/vgic/vgic.h
@@ -27,6 +27,11 @@ static inline bool irq_is_pending(struct vgic_irq *irq)
return irq->pending_latch || irq->line_level;
}
+static inline bool vgic_irq_is_mapped_level(struct vgic_irq *irq)
+{
+ return irq->config == VGIC_CONFIG_LEVEL && irq->hw;
+}
+
struct vgic_irq *vgic_get_irq(struct domain *d, struct vcpu *vcpu,
uint32_t intid);
void vgic_put_irq(struct domain *d, struct vgic_irq *irq);
@@ -41,6 +46,10 @@ static inline void vgic_get_irq_kref(struct vgic_irq *irq)
atomic_inc(&irq->refcount);
}
+void vgic_v2_fold_lr_state(struct vcpu *vcpu);
+void vgic_v2_populate_lr(struct vcpu *vcpu, struct vgic_irq *irq, int lr);
+void vgic_v2_set_underflow(struct vcpu *vcpu);
+
#endif
/*
--
generated by git-patchbot for /home/xen/git/xen.git#master
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