This patch handles some concern cases when the last assigned device
is removed from the domain. In this case we should carefully handle
pi descriptor and the per-cpu blocking list, to make sure:
- all the PI descriptor are in the right state when next time a
devices is assigned to the domain again.
- No remaining vcpus of the domain in the per-cpu blocking list.
Basically, we pause the domain before zapping the PI hooks and
removing the vCPU from the blocking list, then unpause it after
that.
Signed-off-by: Feng Wu <feng...@intel.com>
---
v4:
- Rename some functions:
vmx_pi_remove_vcpu_from_blocking_list() -> vmx_pi_list_remove()
vmx_pi_blocking_cleanup() -> vmx_pi_list_cleanup()
- Remove the check in vmx_pi_list_cleanup()
- Comments adjustment
xen/arch/x86/hvm/vmx/vmx.c | 33 +++++++++++++++++++++++++++++----
1 file changed, 29 insertions(+), 4 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 355936a..7305f40 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -158,14 +158,12 @@ static void vmx_pi_switch_to(struct vcpu *v)
pi_clear_sn(pi_desc);
}
-static void vmx_pi_do_resume(struct vcpu *v)
+static void vmx_pi_list_remove(struct vcpu *v)
{
unsigned long flags;
spinlock_t *pi_blocking_list_lock;
struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
- ASSERT(!test_bit(_VPF_blocked, &v->pause_flags));
-
/*
* Set 'NV' field back to posted_intr_vector, so the
* Posted-Interrupts can be delivered to the vCPU when
@@ -173,12 +171,12 @@ static void vmx_pi_do_resume(struct vcpu *v)
*/
write_atomic(&pi_desc->nv, posted_intr_vector);
- /* The vCPU is not on any blocking list. */
pi_blocking_list_lock = v->arch.hvm_vmx.pi_blocking.lock;
/* Prevent the compiler from eliminating the local variable.*/
smp_rmb();
+ /* The vCPU is not on any blocking list. */
if ( pi_blocking_list_lock == NULL )
return;
@@ -198,6 +196,18 @@ static void vmx_pi_do_resume(struct vcpu *v)
spin_unlock_irqrestore(pi_blocking_list_lock, flags);
}
+static void vmx_pi_do_resume(struct vcpu *v)
+{
+ ASSERT(!test_bit(_VPF_blocked, &v->pause_flags));
+
+ vmx_pi_list_remove(v);
+}
+
+static void vmx_pi_list_cleanup(struct vcpu *v)
+{
+ vmx_pi_list_remove(v);
+}
+
/* This function is called when pcidevs_lock is held */
void vmx_pi_hooks_assign(struct domain *d)
{
@@ -215,13 +225,28 @@ void vmx_pi_hooks_assign(struct domain *d)
/* This function is called when pcidevs_lock is held */
void vmx_pi_hooks_deassign(struct domain *d)
{
+ struct vcpu *v;
+
if ( !iommu_intpost || !has_hvm_container_domain(d) )
return;
ASSERT(d->arch.hvm_domain.vmx.vcpu_block);
+ /*
+ * Pausing the domain can make sure the vCPU is not
+ * running and hence calling the hooks simultaneously
+ * when deassigning the PI hooks and removing the vCPU
+ * from the blocking list.
+ */
+ domain_pause(d);
+
d->arch.hvm_domain.vmx.vcpu_block = NULL;
d->arch.hvm_domain.vmx.pi_do_resume = NULL;
+
+ for_each_vcpu ( d, v )
+ vmx_pi_list_cleanup(v);
+
+ domain_unpause(d);
}
static int vmx_domain_initialise(struct domain *d)
--
2.1.0
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