Extend max vcpu number for HVM guest

Reduce size of Xen-qemu shared ioreq structure to 32 bytes. This
has two advantages:
 1. We can support up to 128 VCPUs with a single shared page
 2. If/when we want to go beyond 128 VCPUs, a whole number of ioreq_t
    structures will pack into a single shared page, so a multi-page
    array will have no ioreq_t straddling a page boundary

Also, while modifying qemu, replace a 32-entry vcpu-indexed array
with a dynamically-allocated array.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

1 files changed, 1 insertions, 3 deletions

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 36653122a8..d257ff3061 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -55,8 +55,7 @@ static int hvmemul_do_io(
     paddr_t value = ram_gpa;
     int value_is_ptr = (p_data == NULL);
     struct vcpu *curr = current;
-    vcpu_iodata_t *vio = get_ioreq(curr);
-    ioreq_t *p = &vio->vp_ioreq;
+    ioreq_t *p = get_ioreq(curr);
     int rc;
 
     /*
@@ -138,7 +137,6 @@ static int hvmemul_do_io(
     p->count = *reps;
     p->df = df;
     p->data = value;
-    p->io_count++;
 
     hvmtrace_io_assist(is_mmio, p);