In preparation of the introduction of new vCPU operations allowing to
register the respective areas (one of the two is x86-specific) by
guest-physical address, add the necessary fork handling (with the
backing function yet to be filled in).
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -1653,6 +1653,65 @@ static void copy_vcpu_nonreg_state(struc
hvm_set_nonreg_state(cd_vcpu, &nrs);
}
+static int copy_guest_area(struct guest_area *cd_area,
+ const struct guest_area *d_area,
+ struct vcpu *cd_vcpu,
+ const struct domain *d)
+{
+ mfn_t d_mfn, cd_mfn;
+
+ if ( !d_area->pg )
+ return 0;
+
+ d_mfn = page_to_mfn(d_area->pg);
+
+ /* Allocate & map a page for the area if it hasn't been already. */
+ if ( !cd_area->pg )
+ {
+ gfn_t gfn = mfn_to_gfn(d, d_mfn);
+ struct p2m_domain *p2m = p2m_get_hostp2m(cd_vcpu->domain);
+ p2m_type_t p2mt;
+ p2m_access_t p2ma;
+ unsigned int offset;
+ int ret;
+
+ cd_mfn = p2m->get_entry(p2m, gfn, &p2mt, &p2ma, 0, NULL, NULL);
+ if ( mfn_eq(cd_mfn, INVALID_MFN) )
+ {
+ struct page_info *pg = alloc_domheap_page(cd_vcpu->domain, 0);
+
+ if ( !pg )
+ return -ENOMEM;
+
+ cd_mfn = page_to_mfn(pg);
+ set_gpfn_from_mfn(mfn_x(cd_mfn), gfn_x(gfn));
+
+ ret = p2m->set_entry(p2m, gfn, cd_mfn, PAGE_ORDER_4K, p2m_ram_rw,
+ p2m->default_access, -1);
+ if ( ret )
+ return ret;
+ }
+ else if ( p2mt != p2m_ram_rw )
+ return -EBUSY;
+
+ /*
+ * Simply specify the entire range up to the end of the page. All the
+ * function uses it for is a check for not crossing page boundaries.
+ */
+ offset = PAGE_OFFSET(d_area->map);
+ ret = map_guest_area(cd_vcpu, gfn_to_gaddr(gfn) + offset,
+ PAGE_SIZE - offset, cd_area, NULL);
+ if ( ret )
+ return ret;
+ }
+ else
+ cd_mfn = page_to_mfn(cd_area->pg);
+
+ copy_domain_page(cd_mfn, d_mfn);
+
+ return 0;
+}
+
static int copy_vpmu(struct vcpu *d_vcpu, struct vcpu *cd_vcpu)
{
struct vpmu_struct *d_vpmu = vcpu_vpmu(d_vcpu);
@@ -1745,6 +1804,16 @@ static int copy_vcpu_settings(struct dom
copy_domain_page(new_vcpu_info_mfn, vcpu_info_mfn);
}
+ /* Same for the (physically registered) runstate and time info areas.
*/
+ ret = copy_guest_area(&cd_vcpu->runstate_guest_area,
+ &d_vcpu->runstate_guest_area, cd_vcpu, d);
+ if ( ret )
+ return ret;
+ ret = copy_guest_area(&cd_vcpu->arch.time_guest_area,
+ &d_vcpu->arch.time_guest_area, cd_vcpu, d);
+ if ( ret )
+ return ret;
+
ret = copy_vpmu(d_vcpu, cd_vcpu);
if ( ret )
return ret;
@@ -1987,7 +2056,10 @@ int mem_sharing_fork_reset(struct domain
state:
if ( reset_state )
+ {
rc = copy_settings(d, pd);
+ /* TBD: What to do here with -ERESTART? */
+ }
domain_unpause(d);
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1572,6 +1572,13 @@ void unmap_vcpu_info(struct vcpu *v)
put_page_and_type(mfn_to_page(mfn));
}
+int map_guest_area(struct vcpu *v, paddr_t gaddr, unsigned int size,
+ struct guest_area *area,
+ void (*populate)(void *dst, struct vcpu *v))
+{
+ return -EOPNOTSUPP;
+}
+
/*
* This is only intended to be used for domain cleanup (or more generally only
* with at least the respective vCPU, if it's not the current one, reliably
