[04/10] viridian: use hypercall_vpmask in hvcall_ipi()

Commit Message

Paul Durrant Nov. 11, 2020, 8:07 p.m. UTC

From: Paul Durrant <[e-mail]>

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 <[e-mail]>
---
Cc: Wei Liu <[e-mail]>
Cc: Jan Beulich <[e-mail]>
Cc: Andrew Cooper <[e-mail]>
Cc: "Roger Pau Monné" <[e-mail]>
---
 xen/arch/x86/hvm/viridian/viridian.c | 43 ++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 8 deletions(-)

Comments

Jan Beulich Nov. 12, 2020, 8:49 a.m. UTC | #1

On 11.11.2020 21:07, Paul Durrant wrote:
> --- a/xen/arch/x86/hvm/viridian/viridian.c
> +++ b/xen/arch/x86/hvm/viridian/viridian.c
> @@ -533,6 +533,21 @@ static bool vpmask_test(struct hypercall_vpmask *vpmask, unsigned int vp)
>      return test_bit(vp, vpmask->mask);
>  }
>  
> +static unsigned int vpmask_first(struct hypercall_vpmask *vpmask)
> +{
> +    return find_first_bit(vpmask->mask, HVM_MAX_VCPUS);
> +}
> +
> +static unsigned int vpmask_next(struct hypercall_vpmask *vpmask, unsigned int vp)
> +{
> +    return find_next_bit(vpmask->mask, HVM_MAX_VCPUS, vp + 1);

Perhaps again assert on vp's range?

> +}
> +
> +#define for_each_vp(vpmask, vp) \
> +	for ((vp) = vpmask_first(vpmask); \
> +	     (vp) < HVM_MAX_VCPUS; \
> +	     (vp) = vpmask_next(vpmask, vp))

Nit again: Missing blanks here and ...

> @@ -669,17 +693,20 @@ static int hvcall_ipi(union hypercall_input *input,
>      if ( vector < 0x10 || vector > 0xff )
>          return -EINVAL;
>  
> -    for_each_vcpu ( currd, v )
> +    vpmask_empty(vpmask);
> +    for (vp = 0; vp < 64; vp++)

... here. I also wonder if the literal 64 couldn't be expressed in
some suitable way.

Jan

Paul Durrant Nov. 19, 2020, 4:04 p.m. UTC | #2

> -----Original Message-----
> From: Jan Beulich <[e-mail]>
> Sent: 12 November 2020 08:50
> To: Paul Durrant <[e-mail]>
> Cc: Paul Durrant <[e-mail]>; Wei Liu <[e-mail]>; Andrew Cooper
> <[e-mail]>; Roger Pau Monné <[e-mail]>; [e-mail]
> Subject: Re: [PATCH 04/10] viridian: use hypercall_vpmask in hvcall_ipi()
> 
> On 11.11.2020 21:07, Paul Durrant wrote:
> > --- a/xen/arch/x86/hvm/viridian/viridian.c
> > +++ b/xen/arch/x86/hvm/viridian/viridian.c
> > @@ -533,6 +533,21 @@ static bool vpmask_test(struct hypercall_vpmask *vpmask, unsigned int vp)
> >      return test_bit(vp, vpmask->mask);
> >  }
> >
> > +static unsigned int vpmask_first(struct hypercall_vpmask *vpmask)
> > +{
> > +    return find_first_bit(vpmask->mask, HVM_MAX_VCPUS);
> > +}
> > +
> > +static unsigned int vpmask_next(struct hypercall_vpmask *vpmask, unsigned int vp)
> > +{
> > +    return find_next_bit(vpmask->mask, HVM_MAX_VCPUS, vp + 1);
> 
> Perhaps again assert on vp's range?
> 

Ok.

> > +}
> > +
> > +#define for_each_vp(vpmask, vp) \
> > +	for ((vp) = vpmask_first(vpmask); \
> > +	     (vp) < HVM_MAX_VCPUS; \
> > +	     (vp) = vpmask_next(vpmask, vp))
> 
> Nit again: Missing blanks here and ...

Oh yes.

> 
> > @@ -669,17 +693,20 @@ static int hvcall_ipi(union hypercall_input *input,
> >      if ( vector < 0x10 || vector > 0xff )
> >          return -EINVAL;
> >
> > -    for_each_vcpu ( currd, v )
> > +    vpmask_empty(vpmask);
> > +    for (vp = 0; vp < 64; vp++)
> 
> ... here. I also wonder if the literal 64 couldn't be expressed in
> some suitable way.
> 

Ok. I'll see if I can suitably macrotize it.

  Paul

> Jan

Patch

diff --git a/xen/arch/x86/hvm/viridian/viridian.c b/xen/arch/x86/hvm/viridian/viridian.c
index 4ab1f14b2248..63f63093a513 100644
--- a/xen/arch/x86/hvm/viridian/viridian.c
+++ b/xen/arch/x86/hvm/viridian/viridian.c
@@ -533,6 +533,21 @@  static bool vpmask_test(struct hypercall_vpmask *vpmask, unsigned int vp)
     return test_bit(vp, vpmask->mask);
 }
 
+static unsigned int vpmask_first(struct hypercall_vpmask *vpmask)
+{
+    return find_first_bit(vpmask->mask, HVM_MAX_VCPUS);
+}
+
+static unsigned int vpmask_next(struct hypercall_vpmask *vpmask, unsigned int vp)
+{
+    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.
@@ -624,15 +639,24 @@  static int hvcall_flush(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(union hypercall_input *input,
                       union hypercall_output *output,
                       unsigned long input_params_gpa,
                       unsigned long 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;
+    unsigned int vp;
 
     /* Get input parameters. */
     if ( input->fast )
@@ -669,17 +693,20 @@  static int hvcall_ipi(union hypercall_input *input,
     if ( vector < 0x10 || vector > 0xff )
         return -EINVAL;
 
-    for_each_vcpu ( currd, v )
+    vpmask_empty(vpmask);
+    for (vp = 0; vp < 64; vp++)
     {
-        if ( v->vcpu_id >= (sizeof(vcpu_mask) * 8) )
-            return -EINVAL;
+        if ( !vcpu_mask )
+            break;
 
-        if ( !(vcpu_mask & (1ul << v->vcpu_id)) )
-            continue;
+        if ( vcpu_mask & 1 )
+            vpmask_set(vpmask, vp);
 
-        vlapic_set_irq(vcpu_vlapic(v), vector, 0);
+        vcpu_mask >>= 1;
     }
 
+    send_ipi(vpmask, vector);
+
     return 0;
 }