---
Changes in v4:
- code style
Changes in v3:
- add in-code comments
- improve existing comments
- remove ifdef around domain_vpl011_init in construct_domU
- add ASSERT
- use SBSA_UART_FIFO_SIZE for in buffer size
- rename ring_enable to backend_in_domain
- rename struct xencons_in to struct vpl011_xen_backend
- rename inring field to xen
- rename helper functions accordingly
- remove unnecessary stub implementation of vpl011_rx_char
- move vpl011_rx_char_xen within the file to avoid the need of a forward
declaration of vpl011_data_avail
- fix small bug in vpl011_rx_char_xen: increment in_prod before using it
to check xencons_queued.
Changes in v2:
- only init if vpl011
- rename vpl011_read_char to vpl011_rx_char
- remove spurious change
- fix coding style
- use different ring struct
- move the write_data changes to their own function
(vpl011_write_data_noring)
- duplicate vpl011_read_data
---
xen/arch/arm/domain_build.c | 9 +-
xen/arch/arm/vpl011.c | 200 +++++++++++++++++++++++++++++++++++++------
xen/include/asm-arm/vpl011.h | 8 ++
3 files changed, 192 insertions(+), 25 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 049ab84..4379538 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2618,7 +2618,14 @@ static int __init construct_domU(struct domain *d,
if ( rc < 0 )
return rc;
- return __construct_domain(d, &kinfo);
+ rc = __construct_domain(d, &kinfo);
+ if ( rc < 0 )
+ return rc;
+
+ if ( kinfo.vpl011 )
+ rc = domain_vpl011_init(d, NULL);
+
+ return rc;
}
void __init create_domUs(void)
diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
index 68452a8..131507e 100644
--- a/xen/arch/arm/vpl011.c
+++ b/xen/arch/arm/vpl011.c
@@ -77,6 +77,91 @@ static void vpl011_update_interrupt_status(struct domain *d)
#endif
}
+/*
+ * vpl011_write_data_xen writes chars from the vpl011 out buffer to the
+ * console. Only to be used when the backend is Xen.
+ */
+static void vpl011_write_data_xen(struct domain *d, uint8_t data)
+{
+ unsigned long flags;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+
+ VPL011_LOCK(d, flags);
+
+ printk("%c", data);
+ if (data == '\n')
+ printk("DOM%u: ", d->domain_id);
+
+ vpl011->uartris |= TXI;
+ vpl011->uartfr &= ~TXFE;
+ vpl011_update_interrupt_status(d);
+
+ VPL011_UNLOCK(d, flags);
+}
+
+/*
+ * vpl011_read_data_xen reads data when the backend is xen. Characters
+ * are added to the vpl011 receive buffer by vpl011_rx_char_xen.
+ */
+static uint8_t vpl011_read_data_xen(struct domain *d)
+{
+ unsigned long flags;
+ uint8_t data = 0;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct vpl011_xen_backend *intf = vpl011->backend.xen;
+ XENCONS_RING_IDX in_cons, in_prod;
+
+ VPL011_LOCK(d, flags);
+
+ in_cons = intf->in_cons;
+ in_prod = intf->in_prod;
+
+ smp_rmb();
+
+ /*
+ * It is expected that there will be data in the ring buffer when this
+ * function is called since the guest is expected to read the data register
+ * only if the TXFE flag is not set.
+ * If the guest still does read when TXFE bit is set then 0 will be
returned.
+ */
+ if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) > 0 )
+ {
+ unsigned int fifo_level;
+
+ data = intf->in[xencons_mask(in_cons, sizeof(intf->in))];
+ in_cons += 1;
+ smp_mb();
+ intf->in_cons = in_cons;
+
+ fifo_level = xencons_queued(in_prod, in_cons, sizeof(intf->in));
+
+ /* If the FIFO is now empty, we clear the receive timeout interrupt. */
+ if ( fifo_level == 0 )
+ {
+ vpl011->uartfr |= RXFE;
+ vpl011->uartris &= ~RTI;
+ }
+
+ /* If the FIFO is more than half empty, we clear the RX interrupt. */
+ if ( fifo_level < sizeof(intf->in) - SBSA_UART_FIFO_LEVEL )
+ vpl011->uartris &= ~RXI;
+
+ vpl011_update_interrupt_status(d);
+ }
+ else
+ gprintk(XENLOG_ERR, "vpl011: Unexpected IN ring buffer empty\n");
+
+ /*
+ * We have consumed a character or the FIFO was empty, so clear the
+ * "FIFO full" bit.
+ */
+ vpl011->uartfr &= ~RXFF;
+
+ VPL011_UNLOCK(d, flags);
+
+ return data;
+}
+
static uint8_t vpl011_read_data(struct domain *d)
{
unsigned long flags;
@@ -240,7 +325,10 @@ static int vpl011_mmio_read(struct vcpu *v,
case DR:
if ( !vpl011_reg32_check_access(dabt) ) goto bad_width;
- *r = vreg_reg32_extract(vpl011_read_data(d), info);
+ if ( vpl011->backend_in_domain )
+ *r = vreg_reg32_extract(vpl011_read_data(d), info);
+ else
+ *r = vreg_reg32_extract(vpl011_read_data_xen(d), info);
return 1;
case RSR:
@@ -325,7 +413,10 @@ static int vpl011_mmio_write(struct vcpu *v,
vreg_reg32_update(&data, r, info);
data &= 0xFF;
- vpl011_write_data(v->domain, data);
+ if ( vpl011->backend_in_domain )
+ vpl011_write_data(v->domain, data);
+ else
+ vpl011_write_data_xen(v->domain, data);
return 1;
}
@@ -430,6 +521,39 @@ static void vpl011_data_avail(struct domain *d,
vpl011->uartfr |= TXFE;
}
+/*
+ * vpl011_rx_char_xen adds a char to a domain's vpl011 receive buffer.
+ * It is only used when the vpl011 backend is in Xen.
+ */
+void vpl011_rx_char_xen(struct domain *d, char c)
+{
+ unsigned long flags;
+ struct vpl011 *vpl011 = &d->arch.vpl011;
+ struct vpl011_xen_backend *intf = vpl011->backend.xen;
+ XENCONS_RING_IDX in_cons, in_prod, in_fifo_level;
+
+ ASSERT(!vpl011->backend_in_domain);
+ VPL011_LOCK(d, flags);
+
+ in_cons = intf->in_cons;
+ in_prod = intf->in_prod;
+ if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) ==
sizeof(intf->in) )
+ {
+ VPL011_UNLOCK(d, flags);
+ return;
+ }
+
+ intf->in[xencons_mask(in_prod, sizeof(intf->in))] = c;
+ intf->in_prod = ++in_prod;
+
+ in_fifo_level = xencons_queued(in_prod,
+ in_cons,
+ sizeof(intf->in));
+
+ vpl011_data_avail(d, in_fifo_level, sizeof(intf->in), 0,
SBSA_UART_FIFO_SIZE);
+ VPL011_UNLOCK(d, flags);
+}
+
static void vpl011_notification(struct vcpu *v, unsigned int port)
{
unsigned long flags;
@@ -470,27 +594,47 @@ int domain_vpl011_init(struct domain *d, struct
vpl011_init_info *info)
if ( vpl011->backend.dom.ring_buf )
return -EINVAL;
- /* Map the guest PFN to Xen address space. */
- rc = prepare_ring_for_helper(d,
- gfn_x(info->gfn),
- &vpl011->backend.dom.ring_page,
- &vpl011->backend.dom.ring_buf);
- if ( rc < 0 )
- goto out;
+ /*
+ * info is NULL when the backend is in Xen.
+ * info is != NULL when the backend is in a domain.
+ */
+ if ( info != NULL )
+ {
+ vpl011->backend_in_domain = true;
+
+ /* Map the guest PFN to Xen address space. */
+ rc = prepare_ring_for_helper(d,
+ gfn_x(info->gfn),
+ &vpl011->backend.dom.ring_page,
+ &vpl011->backend.dom.ring_buf);
+ if ( rc < 0 )
+ goto out;
+
+ rc = alloc_unbound_xen_event_channel(d, 0, info->console_domid,
+ vpl011_notification);
+ if ( rc < 0 )
+ goto out1;
+
+ vpl011->evtchn = info->evtchn = rc;
+ }
+ else
+ {
+ vpl011->backend_in_domain = false;
+
+ vpl011->backend.xen = xzalloc(struct vpl011_xen_backend);
+ if ( vpl011->backend.xen == NULL )
+ {
+ rc = -EINVAL;
+ goto out1;
+ }
+ }
rc = vgic_reserve_virq(d, GUEST_VPL011_SPI);
if ( !rc )
{
rc = -EINVAL;
- goto out1;
- }
-
- rc = alloc_unbound_xen_event_channel(d, 0, info->console_domid,
- vpl011_notification);
- if ( rc < 0 )
goto out2;
-
- vpl011->evtchn = info->evtchn = rc;
+ }
spin_lock_init(&vpl011->lock);
@@ -503,8 +647,11 @@ out2:
vgic_free_virq(d, GUEST_VPL011_SPI);
out1:
- destroy_ring_for_helper(&vpl011->backend.dom.ring_buf,
- vpl011->backend.dom.ring_page);
+ if ( vpl011->backend_in_domain )
+ destroy_ring_for_helper(&vpl011->backend.dom.ring_buf,
+ vpl011->backend.dom.ring_page);
+ else
+ xfree(vpl011->backend.xen);
out:
return rc;
@@ -514,12 +661,17 @@ void domain_vpl011_deinit(struct domain *d)
{
struct vpl011 *vpl011 = &d->arch.vpl011;
- if ( !vpl011->backend.dom.ring_buf )
- return;
+ if ( vpl011->backend_in_domain )
+ {
+ if ( !vpl011->backend.dom.ring_buf )
+ return;
- free_xen_event_channel(d, vpl011->evtchn);
- destroy_ring_for_helper(&vpl011->backend.dom.ring_buf,
- vpl011->backend.dom.ring_page);
+ free_xen_event_channel(d, vpl011->evtchn);
+ destroy_ring_for_helper(&vpl011->backend.dom.ring_buf,
+ vpl011->backend.dom.ring_page);
+ }
+ else
+ xfree(vpl011->backend.xen);
}
/*
diff --git a/xen/include/asm-arm/vpl011.h b/xen/include/asm-arm/vpl011.h
index 42d7a24..5eb6d25 100644
--- a/xen/include/asm-arm/vpl011.h
+++ b/xen/include/asm-arm/vpl011.h
@@ -21,6 +21,7 @@
#include <public/domctl.h>
#include <public/io/ring.h>
+#include <public/io/console.h>
#include <asm/vreg.h>
#include <xen/mm.h>
@@ -29,13 +30,19 @@
#define VPL011_UNLOCK(d,flags) spin_unlock_irqrestore(&(d)->arch.vpl011.lock,
flags)
#define SBSA_UART_FIFO_SIZE 32
+struct vpl011_xen_backend {
+ char in[SBSA_UART_FIFO_SIZE];
+ XENCONS_RING_IDX in_cons, in_prod;
+};
struct vpl011 {
+ bool backend_in_domain;
union {
struct {
void *ring_buf;
struct page_info *ring_page;
} dom;
+ struct vpl011_xen_backend *xen;
} backend;
uint32_t uartfr; /* Flag register */
uint32_t uartcr; /* Control register */
@@ -57,6 +64,7 @@ struct vpl011_init_info {
int domain_vpl011_init(struct domain *d,
struct vpl011_init_info *info);
void domain_vpl011_deinit(struct domain *d);
+void vpl011_rx_char_xen(struct domain *d, char c);
#else
static inline int domain_vpl011_init(struct domain *d,
struct vpl011_init_info *info)
