Copies from source grant reference to dest grant reference (or the
other way around.)
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
arch/x86/kvm/xen.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 151 insertions(+)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 8f06924e0dfa..fecc548b2f12 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -10,6 +10,7 @@
#include "ioapic.h"
#include <linux/mman.h>
+#include <linux/highmem.h>
#include <linux/kvm_host.h>
#include <linux/eventfd.h>
#include <linux/sched/stat.h>
@@ -1747,6 +1748,148 @@ static int shim_hcall_gntunmap(struct kvm_xen *xen,
return 0;
}
+static unsigned long __kvm_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+ struct kvm_xen *xen = vcpu ? &vcpu->kvm->arch.xen : xen_shim;
+ unsigned long hva;
+
+ if (xen->domid == 0)
+ return (unsigned long) page_to_virt(pfn_to_page(gfn));
+
+ hva = gfn_to_hva(vcpu->kvm, gfn);
+ if (unlikely(kvm_is_error_hva(hva)))
+ return 0;
+
+ return hva;
+}
+
+static int __kvm_gref_to_page(struct kvm_vcpu *vcpu, grant_ref_t ref,
+ domid_t domid, struct page **page,
+ int16_t *status)
+{
+ struct kvm_xen *source = vcpu ? &vcpu->kvm->arch.xen : xen_shim;
+ struct grant_entry_v1 *shah;
+ struct grant_entry_v1 **gt;
+ struct kvm *dest;
+
+ dest = kvm_xen_find_vm(domid);
+ if (unlikely(!dest)) {
+ pr_err("gnttab: could not find domain %u\n", domid);
+ *status = GNTST_bad_domain;
+ return 0;
+ }
+
+ if (unlikely(ref >= gnttab_entries(dest))) {
+ pr_err("gnttab: bad ref %u\n", ref);
+ *status = GNTST_bad_gntref;
+ return 0;
+ }
+
+ gt = dest->arch.xen.gnttab.frames_v1;
+ shah = shared_entry(gt, ref);
+ if (unlikely(shah->domid != source->domid)) {
+ pr_err("gnttab: bad domain (%u != %u)\n",
+ shah->domid, source->domid);
+ *status = GNTST_bad_gntref;
+ return 0;
+ }
+
+ (void) map_grant_nosleep(dest, shah->frame, 0, page, status);
+
+ return 0;
+}
+
+static int shim_hcall_gntcopy(struct kvm_vcpu *vcpu,
+ struct gnttab_copy *op)
+{
+ void *saddr = NULL, *daddr = NULL;
+ struct page *spage = NULL, *dpage = NULL;
+ unsigned long hva;
+ int err = -ENOSYS;
+ gfn_t gfn;
+
+ if (!(op->flags & GNTCOPY_source_gref) &&
+ (op->source.domid == DOMID_SELF)) {
+ gfn = op->source.u.gmfn;
+ hva = __kvm_gfn_to_hva(vcpu, gfn);
+ if (unlikely(!hva)) {
+ pr_err("gnttab: bad source gfn:%llx\n", gfn);
+ op->status = GNTST_general_error;
+ err = 0;
+ return 0;
+ }
+
+ saddr = (void *) (((unsigned long) hva) + op->source.offset);
+ } else if (op->flags & GNTCOPY_source_gref) {
+ op->status = GNTST_okay;
+ if (__kvm_gref_to_page(vcpu, op->source.u.ref,
+ op->source.domid, &spage, &op->status))
+ return -EFAULT;
+
+ if (!spage || op->status != GNTST_okay) {
+ pr_err("gnttab: failed to get page for source gref:%x\n",
+ op->source.u.ref);
+ err = 0;
+ goto out;
+ }
+
+ saddr = kmap(spage);
+ saddr = (void *) (((unsigned long) saddr) + op->source.offset);
+ }
+
+ if (!(op->flags & GNTCOPY_dest_gref) &&
+ (op->dest.domid == DOMID_SELF)) {
+ gfn = op->dest.u.gmfn;
+ hva = __kvm_gfn_to_hva(vcpu, gfn);
+ if (unlikely(!hva)) {
+ pr_err("gnttab: bad dest gfn:%llx\n", gfn);
+ op->status = GNTST_general_error;
+ err = 0;
+ return 0;
+ }
+
+ daddr = (void *) (((unsigned long) hva) + op->dest.offset);
+ } else if (op->flags & GNTCOPY_dest_gref) {
+ op->status = GNTST_okay;
+ if (__kvm_gref_to_page(vcpu, op->dest.u.ref,
+ op->dest.domid, &dpage, &op->status))
+ return -EFAULT;
+
+ if (!dpage || op->status != GNTST_okay) {
+ pr_err("gnttab: failed to get page for dest gref:%x\n",
+ op->dest.u.ref);
+ err = 0;
+ goto out;
+ }
+
+ daddr = kmap(dpage);
+ daddr = (void *) (((unsigned long) daddr) + op->dest.offset);
+ }
+
+ if (unlikely(!daddr || !saddr)) {
+ op->status = GNTST_general_error;
+ err = 0;
+ goto out;
+ }
+
+ memcpy(daddr, saddr, op->len);
+
+ if (spage)
+ kunmap(spage);
+ if (dpage)
+ kunmap(dpage);
+
+
+ err = 0;
+ op->status = GNTST_okay;
+out:
+ if (spage)
+ put_page(spage);
+ if (dpage)
+ put_page(dpage);
+ return err;
+}
+
static int shim_hcall_gnttab(int op, void *p, int count)
{
int ret = -ENOSYS;
@@ -1771,6 +1914,14 @@ static int shim_hcall_gnttab(int op, void *p, int count)
ret = 0;
break;
}
+ case GNTTABOP_copy: {
+ struct gnttab_copy *op = p;
+
+ for (i = 0; i < count; i++)
+ shim_hcall_gntcopy(NULL, op + i);
+ ret = 0;
+ break;
+ }
default:
pr_info("lcall-gnttab:op default=%d\n", op);
break;
--
2.11.0
