Currently, blocked vCPUs are added to PI blocking list if its
domain has assign devices. Actually, some blocked vCPUs will not
be woken up by wakeup interrupt generated by VT-d hardware. They
may be woken up by IPIs or other interrupts from emulated devices.
For these vCPUs we don't add them to PI blocking list.
If a vCPU is blocked prior to its getting bound with a IRTE, we need
adding this vCPU to blocking list when we bind a vCPU with a IRTE.
In that case, arch_vcpu_block() may be called from another vCPU which
the current implementation can't handle. This patch expands the
arch_vcpu_block(), removing some restrictions expressed by
assertions and handling the target vCPU according to its state and
its PI blocking list lock (v->arch.hvm_vmx.pi_blocking.lock).
Signed-off-by: Chao Gao <chao....@intel.com>
---
xen/arch/x86/hvm/vmx/vmx.c | 21 ++++++++++++++-------
xen/drivers/passthrough/vtd/intremap.c | 19 +++++++++++++++++++
2 files changed, 33 insertions(+), 7 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 76cb421..ae16f39 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -125,6 +125,14 @@ static void vmx_vcpu_block(struct vcpu *v)
struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
spinlock_t *pi_blocking_list_lock;
+ /* If no IRTE refers to 'pi_desc', no further operation needs */
+ if ( v->domain->arch.hvm_domain.pi_ops.in_use &&
+ !v->domain->arch.hvm_domain.pi_ops.in_use(v) )
+ return;
+
+ if ( !test_bit(_VPF_blocked, &v->pause_flags) )
+ return;
+
/*
* After pCPU goes down, the per-cpu PI blocking list is cleared.
* To make sure the parameter vCPU is added to the chosen pCPU's
@@ -144,13 +152,8 @@ static void vmx_vcpu_block(struct vcpu *v)
old_lock = cmpxchg(&v->arch.hvm_vmx.pi_blocking.lock, NULL,
pi_blocking_list_lock);
-
- /*
- * 'v->arch.hvm_vmx.pi_blocking.lock' should be NULL before
- * being assigned to a new value, since the vCPU is currently
- * running and it cannot be on any blocking list.
- */
- ASSERT(old_lock == NULL);
+ if ( old_lock )
+ goto out;
atomic_inc(&per_cpu(vmx_pi_blocking, dest_cpu).counter);
HVMTRACE_4D(VT_D_PI_BLOCK, v->domain->domain_id, v->vcpu_id, dest_cpu,
@@ -171,6 +174,10 @@ static void vmx_vcpu_block(struct vcpu *v)
write_atomic(&pi_desc->nv, pi_wakeup_vector);
write_atomic(&pi_desc->ndst,
(x2apic_enabled ? dest : MASK_INSR(dest,
PI_xAPIC_NDST_MASK)));
+ return;
+
+ out:
+ spin_unlock_irqrestore(pi_blocking_list_lock, flags);
}
static void vmx_pi_switch_from(struct vcpu *v)
diff --git a/xen/drivers/passthrough/vtd/intremap.c
b/xen/drivers/passthrough/vtd/intremap.c
index 99f1cce..c43cfa2 100644
--- a/xen/drivers/passthrough/vtd/intremap.c
+++ b/xen/drivers/passthrough/vtd/intremap.c
@@ -30,6 +30,7 @@
#include "extern.h"
#include <asm/apic.h>
+#include <asm/hvm/hvm.h>
#include <asm/io_apic.h>
#define nr_ioapic_entries(i) nr_ioapic_entries[i]
@@ -622,6 +623,20 @@ static void pi_put_ref(struct pi_desc *pi_desc)
v->domain->arch.hvm_domain.pi_ops.put_ref(v);
}
+static bool pi_in_use(struct pi_desc *pi_desc)
+{
+ struct vcpu *v;
+
+ if ( !pi_desc )
+ return 0;
+
+ v = pi_desc_to_vcpu(pi_desc);
+ ASSERT(is_hvm_domain(v->domain));
+ if ( v->domain->arch.hvm_domain.pi_ops.in_use )
+ return v->domain->arch.hvm_domain.pi_ops.in_use(v);
+ return 0;
+}
+
static int msi_msg_to_remap_entry(
struct iommu *iommu, struct pci_dev *pdev,
struct msi_desc *msi_desc, struct msi_msg *msg)
@@ -996,6 +1011,7 @@ int pi_update_irte(struct pi_desc *pi_desc, const struct
pirq *pirq,
struct msi_desc *msi_desc;
struct pi_desc *old_pi_desc;
int rc;
+ bool first_ref;
desc = pirq_spin_lock_irq_desc(pirq, NULL);
if ( !desc )
@@ -1009,7 +1025,10 @@ int pi_update_irte(struct pi_desc *pi_desc, const struct
pirq *pirq,
}
old_pi_desc = msi_desc->pi_desc;
+ first_ref = !pi_in_use(pi_desc);
pi_get_ref(pi_desc);
+ if ( pi_desc && first_ref )
+ arch_vcpu_block(pi_desc_to_vcpu(pi_desc));
msi_desc->pi_desc = pi_desc;
msi_desc->gvec = gvec;
--
1.8.3.1
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