Mailing List Archive

From: Paul Durrant <pdurrant@amazon.com>

A subsequent patch will need to IPI a mask of virtual processors potentially
wider than 64 bits. A previous patch introduced per-cpu hypercall_vpmask
to allow hvcall_flush() to deal with such wide masks. This patch modifies
the implementation of hvcall_ipi() to make use of the same mask structures,
introducing a for_each_vp() macro to facilitate traversing a mask.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Wei Liu <wl@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>

v3:
- Couple of extra 'const' qualifiers

v2:
- Drop the 'vp' loop now that vpmask_set() will do it internally
---
xen/arch/x86/hvm/viridian/viridian.c | 44 +++++++++++++++++++++-------
1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/hvm/viridian/viridian.c b/xen/arch/x86/hvm/viridian/viridian.c
index d8f47b8528a2..cdfeaec8b96b 100644
--- a/xen/arch/x86/hvm/viridian/viridian.c
+++ b/xen/arch/x86/hvm/viridian/viridian.c
@@ -551,6 +551,26 @@ static bool vpmask_test(const struct hypercall_vpmask *vpmask,
return test_bit(vp, vpmask->mask);
}

+static unsigned int vpmask_first(const struct hypercall_vpmask *vpmask)
+{
+ return find_first_bit(vpmask->mask, HVM_MAX_VCPUS);
+}
+
+static unsigned int vpmask_next(const struct hypercall_vpmask *vpmask,
+ unsigned int vp)
+{
+ /*
+ * If vp + 1 > HVM_MAX_VCPUS then find_next_bit() will return
+ * HVM_MAX_VCPUS, ensuring the for_each_vp ( ... ) loop terminates.
+ */
+ return find_next_bit(vpmask->mask, HVM_MAX_VCPUS, vp + 1);
+}
+
+#define for_each_vp(vpmask, vp) \
+ for ( (vp) = vpmask_first(vpmask); \
+ (vp) < HVM_MAX_VCPUS; \
+ (vp) = vpmask_next(vpmask, vp) )
+
/*
* Windows should not issue the hypercalls requiring this callback in the
* case where vcpu_id would exceed the size of the mask.
@@ -631,13 +651,21 @@ static int hvcall_flush(const union hypercall_input *input,
return 0;
}

+static void send_ipi(struct hypercall_vpmask *vpmask, uint8_t vector)
+{
+ struct domain *currd = current->domain;
+ unsigned int vp;
+
+ for_each_vp ( vpmask, vp )
+ vlapic_set_irq(vcpu_vlapic(currd->vcpu[vp]), vector, 0);
+}
+
static int hvcall_ipi(const union hypercall_input *input,
union hypercall_output *output,
paddr_t input_params_gpa,
paddr_t output_params_gpa)
{
- struct domain *currd = current->domain;
- struct vcpu *v;
+ struct hypercall_vpmask *vpmask = &this_cpu(hypercall_vpmask);
uint32_t vector;
uint64_t vcpu_mask;

@@ -676,16 +704,10 @@ static int hvcall_ipi(const union hypercall_input *input,
if ( vector < 0x10 || vector > 0xff )
return -EINVAL;

- for_each_vcpu ( currd, v )
- {
- if ( v->vcpu_id >= (sizeof(vcpu_mask) * 8) )
- return -EINVAL;
+ vpmask_empty(vpmask);
+ vpmask_set(vpmask, 0, vcpu_mask);

- if ( !(vcpu_mask & (1ul << v->vcpu_id)) )
- continue;
-
- vlapic_set_irq(vcpu_vlapic(v), vector, 0);
- }
+ send_ipi(vpmask, vector);

return 0;
}
--
2.20.1