diff mbox

[Xen-devel,v2,3/3] xen/arm: Find automatically a PPI for the DOM0 event channel interrupt

Message ID 1421353422-13133-4-git-send-email-julien.grall@linaro.org
State Superseded, archived
Headers show

Commit Message

Julien Grall Jan. 15, 2015, 8:23 p.m. UTC 
Use the new vgic interface to know which virtual PPI is free and use it
for the event channel code.

At the DOM0 creation time, Xen still don't know which vIRQ will be free.
All the vIRQ will be reserved when we parse the device tree. So allocate
when the hypervisor node is created.

It's safe to defer the allocation because no vIRQ can be injected as
long as the vCPU is not online.

Also correct the check in arch_domain_create to use is_hardware_domain.

Signed-off-by: Julien Grall <julien.grall@linaro.org>

---
    Changes in v2:
        - Correct the BUG_ON in arch_domain_create
        - Use if (...) BUG() rather than BUG_ON()
---
 xen/arch/arm/domain.c                | 17 +++++++++++------
 xen/arch/arm/domain_build.c          | 10 ++++++++++
 xen/arch/arm/platform.c              |  7 -------
 xen/arch/arm/platforms/xgene-storm.c |  1 -
 xen/include/asm-arm/platform.h       |  4 ----
 5 files changed, 21 insertions(+), 18 deletions(-)

Comments

Julien Grall Jan. 19, 2015, 4:19 p.m. UTC | #1 
Hi Ian,

On 19/01/15 16:04, Ian Campbell wrote:
> On Thu, 2015-01-15 at 20:23 +0000, Julien Grall wrote:
> 
> Subject should be "Automatically find..."
> 
>> Use the new vgic interface to know which virtual PPI is free and use it
>> for the event channel code.
>>
>> At the DOM0 creation time, Xen still don't know which vIRQ will be free.
> 
> "...Xen still doesn't know..." or just "... Xen doesn't know..."

I will use the second suggestion.

> 
>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
>> index 3d4f317..d5959b5 100644
>> --- a/xen/arch/arm/domain_build.c
>> +++ b/xen/arch/arm/domain_build.c
>> @@ -627,6 +627,16 @@ static int make_hypervisor_node(struct domain *d,
> 
> I'd prefer this not to be done in make_hypervisor_node, to keep
> make_*_node purely about creating the DT, without other side effects, as
> far as possible.
> 
> I think you can drop a placeholder here and update it around the time of
> the calls to kernel_load and initrd_load from a new helper function
> which allocates and updates. initrd_load does something similar.

I will give a look.

Regards,
diff mbox

Patch

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index d0229d1..046cc78 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -543,13 +543,18 @@  int arch_domain_create(struct domain *d, unsigned int domcr_flags)
     if ( (rc = domain_vtimer_init(d)) != 0 )
         goto fail;
 
-    if ( d->domain_id )
+    /*
+     * The hardware domain will get a PPI later in
+     * arch/arm/domain_build.c  depending on the
+     * interrupt map of the hardware.
+     */
+    if ( !is_hardware_domain(d) )
+    {
         d->arch.evtchn_irq = GUEST_EVTCHN_PPI;
-    else
-        d->arch.evtchn_irq = platform_dom0_evtchn_ppi();
-
-    if ( !vgic_reserve_virq(d, d->arch.evtchn_irq) )
-        BUG();
+        /* At this stage vgic_reserve_virq should never fail */
+        if ( !vgic_reserve_virq(d, GUEST_EVTCHN_PPI) )
+            BUG();
+    }
 
     /*
      * Virtual UART is only used by linux early printk and decompress code.
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 3d4f317..d5959b5 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -627,6 +627,16 @@  static int make_hypervisor_node(struct domain *d,
         return res;
 
     /*
+     * The allocation of the event channel IRQ has been deferred until
+     * now. At this time, all PPIs use by DOM0 has been registered
+     */
+    res = vgic_allocate_virq(d, 0);
+    if ( res < 0 )
+        return -FDT_ERR_XEN(ENOSPC);
+
+    d->arch.evtchn_irq = res;
+
+    /*
      * interrupts is evtchn upcall:
      *  - Active-low level-sensitive
      *  - All cpus
diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c
index cb4cda8..d016797 100644
--- a/xen/arch/arm/platform.c
+++ b/xen/arch/arm/platform.c
@@ -160,13 +160,6 @@  bool_t platform_device_is_blacklisted(const struct dt_device_node *node)
     return dt_match_node(blacklist, node);
 }
 
-unsigned int platform_dom0_evtchn_ppi(void)
-{
-    if ( platform && platform->dom0_evtchn_ppi )
-        return platform->dom0_evtchn_ppi;
-    return GUEST_EVTCHN_PPI;
-}
-
 void platform_dom0_gnttab(paddr_t *start, paddr_t *size)
 {
     if ( platform && platform->dom0_gnttab_size )
diff --git a/xen/arch/arm/platforms/xgene-storm.c b/xen/arch/arm/platforms/xgene-storm.c
index ef3ba63..eee650e 100644
--- a/xen/arch/arm/platforms/xgene-storm.c
+++ b/xen/arch/arm/platforms/xgene-storm.c
@@ -232,7 +232,6 @@  PLATFORM_START(xgene_storm, "APM X-GENE STORM")
     .quirks = xgene_storm_quirks,
     .specific_mapping = xgene_storm_specific_mapping,
 
-    .dom0_evtchn_ppi = 24,
     .dom0_gnttab_start = 0x1f800000,
     .dom0_gnttab_size = 0x20000,
 PLATFORM_END
diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h
index eefaca6..4eba37b 100644
--- a/xen/include/asm-arm/platform.h
+++ b/xen/include/asm-arm/platform.h
@@ -38,10 +38,6 @@  struct platform_desc {
      */
     const struct dt_device_match *blacklist_dev;
     /*
-     * The IRQ (PPI) to use to inject event channels to dom0.
-     */
-    unsigned int dom0_evtchn_ppi;
-    /*
      * The location of a region of physical address space which dom0
      * can use for grant table mappings. If size is zero defaults to
      * 0xb0000000-0xb0020000.