Mailing List Archive

From: Paul Durrant <pdurrant@amazon.com>

... and make use of them in hvcall_flush()/need_flush().

Subsequent patches will need to deal with virtual processor masks potentially
wider than 64 bits. Thus, to avoid using too much stack, this patch
introduces global per-cpu virtual processor masks and converts the
implementation of hvcall_flush() to use them.

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>
---
xen/arch/x86/hvm/viridian/viridian.c | 51 +++++++++++++++++++++++++---
1 file changed, 47 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/hvm/viridian/viridian.c b/xen/arch/x86/hvm/viridian/viridian.c
index c4f720f58d6d..4ab1f14b2248 100644
--- a/xen/arch/x86/hvm/viridian/viridian.c
+++ b/xen/arch/x86/hvm/viridian/viridian.c
@@ -507,15 +507,41 @@ void viridian_domain_deinit(struct domain *d)
XFREE(d->arch.hvm.viridian);
}

+struct hypercall_vpmask {
+ DECLARE_BITMAP(mask, HVM_MAX_VCPUS);
+};
+
+static DEFINE_PER_CPU(struct hypercall_vpmask, hypercall_vpmask);
+
+static void vpmask_empty(struct hypercall_vpmask *vpmask)
+{
+ bitmap_zero(vpmask->mask, HVM_MAX_VCPUS);
+}
+
+static void vpmask_set(struct hypercall_vpmask *vpmask, unsigned int vp)
+{
+ __set_bit(vp, vpmask->mask);
+}
+
+static void vpmask_fill(struct hypercall_vpmask *vpmask)
+{
+ bitmap_fill(vpmask->mask, HVM_MAX_VCPUS);
+}
+
+static bool vpmask_test(struct hypercall_vpmask *vpmask, unsigned int vp)
+{
+ return test_bit(vp, vpmask->mask);
+}
+
/*
* Windows should not issue the hypercalls requiring this callback in the
* case where vcpu_id would exceed the size of the mask.
*/
static bool need_flush(void *ctxt, struct vcpu *v)
{
- uint64_t vcpu_mask = *(uint64_t *)ctxt;
+ struct hypercall_vpmask *vpmask = ctxt;

- return vcpu_mask & (1ul << v->vcpu_id);
+ return vpmask_test(vpmask, v->vcpu_id);
}

union hypercall_input {
@@ -546,6 +572,7 @@ static int hvcall_flush(union hypercall_input *input,
unsigned long input_params_gpa,
unsigned long output_params_gpa)
{
+ struct hypercall_vpmask *vpmask = &this_cpu(hypercall_vpmask);
struct {
uint64_t address_space;
uint64_t flags;
@@ -567,13 +594,29 @@ static int hvcall_flush(union hypercall_input *input,
* so err on the safe side.
*/
if ( input_params.flags & HV_FLUSH_ALL_PROCESSORS )
- input_params.vcpu_mask = ~0ul;
+ vpmask_fill(vpmask);
+ else
+ {
+ unsigned int vp;
+
+ vpmask_empty(vpmask);
+ for (vp = 0; vp < 64; vp++)
+ {
+ if ( !input_params.vcpu_mask )
+ break;
+
+ if ( input_params.vcpu_mask & 1 )
+ vpmask_set(vpmask, vp);
+
+ input_params.vcpu_mask >>= 1;
+ }
+ }

/*
* A false return means that another vcpu is currently trying
* a similar operation, so back off.
*/
- if ( !paging_flush_tlb(need_flush, &input_params.vcpu_mask) )
+ if ( !paging_flush_tlb(need_flush, vpmask) )
return -ERESTART;

output->rep_complete = input->rep_count;
--
2.20.1