(+ Paul and Andre)
Hi,
Adding Paul as the author of DMOP and Andre as this is GIC related.
On 10/09/2020 21:22, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
Looking at the PoC I shared with you, this code was originally written
by me.
This patch adds ability to the device emulator to notify otherend
(some entity running in the guest) using a SPI and implements Arm
specific bits for it. Proposed interface allows emulator to set
the logical level of a one of a domain's IRQ lines.
It would be good to explain in the commit message why we can't use the
existing DMOP to inject an interrupt.
Signed-off-by: Julien Grall <julien.gr...@arm.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"
Please note, I left interface untouched since there is still
an open discussion what interface to use/what information to pass
to the hypervisor. The question whether we should abstract away
the state of the line or not.
Changes RFC -> V1:
- check incoming parameters in arch_dm_op()
- add explicit padding to struct xen_dm_op_set_irq_level
---
---
tools/libs/devicemodel/core.c | 18 +++++++++++++
tools/libs/devicemodel/include/xendevicemodel.h | 4 +++
tools/libs/devicemodel/libxendevicemodel.map | 1 +
xen/arch/arm/dm.c | 36 ++++++++++++++++++++++++-
xen/common/dm.c | 1 +
xen/include/public/hvm/dm_op.h | 15 +++++++++++
6 files changed, 74 insertions(+), 1 deletion(-)
diff --git a/tools/libs/devicemodel/core.c b/tools/libs/devicemodel/core.c
index 4d40639..30bd79f 100644
--- a/tools/libs/devicemodel/core.c
+++ b/tools/libs/devicemodel/core.c
@@ -430,6 +430,24 @@ int xendevicemodel_set_isa_irq_level(
return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
}
+int xendevicemodel_set_irq_level(
+ xendevicemodel_handle *dmod, domid_t domid, uint32_t irq,
+ unsigned int level)
+{
+ struct xen_dm_op op;
+ struct xen_dm_op_set_irq_level *data;
+
+ memset(&op, 0, sizeof(op));
+
+ op.op = XEN_DMOP_set_irq_level;
+ data = &op.u.set_irq_level;
+
+ data->irq = irq;
+ data->level = level;
+
+ return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
+}
+
int xendevicemodel_set_pci_link_route(
xendevicemodel_handle *dmod, domid_t domid, uint8_t link, uint8_t irq)
{
diff --git a/tools/libs/devicemodel/include/xendevicemodel.h
b/tools/libs/devicemodel/include/xendevicemodel.h
index e877f5c..c06b3c8 100644
--- a/tools/libs/devicemodel/include/xendevicemodel.h
+++ b/tools/libs/devicemodel/include/xendevicemodel.h
@@ -209,6 +209,10 @@ int xendevicemodel_set_isa_irq_level(
xendevicemodel_handle *dmod, domid_t domid, uint8_t irq,
unsigned int level);
+int xendevicemodel_set_irq_level(
+ xendevicemodel_handle *dmod, domid_t domid, unsigned int irq,
+ unsigned int level);
+
/**
* This function maps a PCI INTx line to a an IRQ line.
*
diff --git a/tools/libs/devicemodel/libxendevicemodel.map
b/tools/libs/devicemodel/libxendevicemodel.map
index 561c62d..a0c3012 100644
--- a/tools/libs/devicemodel/libxendevicemodel.map
+++ b/tools/libs/devicemodel/libxendevicemodel.map
@@ -32,6 +32,7 @@ VERS_1.2 {
global:
xendevicemodel_relocate_memory;
xendevicemodel_pin_memory_cacheattr;
+ xendevicemodel_set_irq_level;
} VERS_1.1;
VERS_1.3 {
diff --git a/xen/arch/arm/dm.c b/xen/arch/arm/dm.c
index eb20344..428ef98 100644
--- a/xen/arch/arm/dm.c
+++ b/xen/arch/arm/dm.c
@@ -15,11 +15,45 @@
*/
#include <xen/hypercall.h>
NIT: newline between <xen/*> and <asm/*> includes.
+#include <asm/vgic.h>
int arch_dm_op(struct xen_dm_op *op, struct domain *d,
const struct dmop_args *op_args, bool *const_op)
{
- return -EOPNOTSUPP;
+ int rc;
+
+ switch ( op->op )
+ {
+ case XEN_DMOP_set_irq_level:
+ {
+ const struct xen_dm_op_set_irq_level *data =
+ &op->u.set_irq_level;
+
+ /* Only SPIs are supported */
+ if ( (data->irq < NR_LOCAL_IRQS) || (data->irq >= vgic_num_irqs(d)) )
+ {
+ rc = -EINVAL;
+ break;
+ }
+
+ if ( data->level != 0 && data->level != 1 )
+ {
+ rc = -EINVAL;
+ break;
+ }
+
I think we want to check the padding is always 0.
+
+ vgic_inject_irq(d, NULL, data->irq, data->level);
So, this interface will allow the device emulator to raise/lower the
line for an HW mapped interrupt. I think this will mess up with the
internal state machine.
It would probably be better if a device emulator can only raise/lower
the line for non-allocated interrupts (see d->arch.vgic.allocated_irqs).
Any thoughts?
+ rc = 0;
+ break;
+ }
+
+ default:
+ rc = -EOPNOTSUPP;
+ break;
+ }
+
+ return rc;
}
/*
diff --git a/xen/common/dm.c b/xen/common/dm.c
index 060731d..c55e042 100644
--- a/xen/common/dm.c
+++ b/xen/common/dm.c
@@ -47,6 +47,7 @@ static int dm_op(const struct dmop_args *op_args)
[XEN_DMOP_remote_shutdown] = sizeof(struct
xen_dm_op_remote_shutdown),
[XEN_DMOP_relocate_memory] = sizeof(struct
xen_dm_op_relocate_memory),
[XEN_DMOP_pin_memory_cacheattr] = sizeof(struct
xen_dm_op_pin_memory_cacheattr),
+ [XEN_DMOP_set_irq_level] = sizeof(struct
xen_dm_op_set_irq_level),
};
rc = rcu_lock_remote_domain_by_id(op_args->domid, &d);
diff --git a/xen/include/public/hvm/dm_op.h b/xen/include/public/hvm/dm_op.h
index fd00e9d..39567bf 100644
--- a/xen/include/public/hvm/dm_op.h
+++ b/xen/include/public/hvm/dm_op.h
@@ -417,6 +417,20 @@ struct xen_dm_op_pin_memory_cacheattr {
uint32_t pad;
};
+/*
+ * XEN_DMOP_set_irq_level: Set the logical level of a one of a domain's
+ * IRQ lines.
+ * XXX Handle PPIs.
This is a public interface, so it seems a bit strange to leave a TODO in
this code.
I wouldn't be surprised if someone will want PPI support soon, but we
may be able to defer it if we can easily extend the hypercall.
@Paul, how did you envision to extend DMOP?
Also, is there any plan to add x86 support? If not, then I think we want
to document in the interface that this is Arm only.
+ */
+#define XEN_DMOP_set_irq_level 19
+
+struct xen_dm_op_set_irq_level {
+ uint32_t irq;
+ /* IN - Level: 0 -> deasserted, 1 -> asserted */
+ uint8_t level;
+ uint8_t pad[3];
+};
+
struct xen_dm_op {
uint32_t op;
uint32_t pad;
@@ -430,6 +444,7 @@ struct xen_dm_op {
struct xen_dm_op_track_dirty_vram track_dirty_vram;
struct xen_dm_op_set_pci_intx_level set_pci_intx_level;
struct xen_dm_op_set_isa_irq_level set_isa_irq_level;
+ struct xen_dm_op_set_irq_level set_irq_level;
struct xen_dm_op_set_pci_link_route set_pci_link_route;
struct xen_dm_op_modified_memory modified_memory;
struct xen_dm_op_set_mem_type set_mem_type;
Cheers,
--
Julien Grall