i386/xen: implement XENMEM_add_to_physmap_batch

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

target/i386/kvm/xen-compat.h

@@ -15,6 +15,20 @@
 
 typedef uint32_t compat_pfn_t;
 typedef uint32_t compat_ulong_t;
+typedef uint32_t compat_ptr_t;
+
+#define __DEFINE_COMPAT_HANDLE(name, type)      \
+    typedef struct {                            \
+        compat_ptr_t c;                         \
+        type *_[0] __attribute__((packed));   \
+    } __compat_handle_ ## name;                 \
+
+#define DEFINE_COMPAT_HANDLE(name) __DEFINE_COMPAT_HANDLE(name, name)
+#define COMPAT_HANDLE(name) __compat_handle_ ## name
+
+DEFINE_COMPAT_HANDLE(compat_pfn_t);
+DEFINE_COMPAT_HANDLE(compat_ulong_t);
+DEFINE_COMPAT_HANDLE(int);
 
 struct compat_xen_add_to_physmap {
     domid_t domid;
@@ -24,4 +38,14 @@ struct compat_xen_add_to_physmap {
     compat_pfn_t gpfn;
 };
 
+struct compat_xen_add_to_physmap_batch {
+    domid_t domid;
+    uint16_t space;
+    uint16_t size;
+    uint16_t extra;
+    COMPAT_HANDLE(compat_ulong_t) idxs;
+    COMPAT_HANDLE(compat_pfn_t) gpfns;
+    COMPAT_HANDLE(int) errs;
+};
+
 #endif /* QEMU_I386_XEN_COMPAT_H */

target/i386/kvm/xen-emu.c

@@ -262,6 +262,71 @@ static int do_add_to_physmap(struct kvm_xen_exit *exit, X86CPU *cpu,
     return add_to_physmap_one(xatp.space, xatp.idx, xatp.gpfn);
 }
 
+static int do_add_to_physmap_batch(struct kvm_xen_exit *exit, X86CPU *cpu,
+                                   uint64_t arg)
+{
+    struct xen_add_to_physmap_batch xatpb;
+    unsigned long idxs_gva, gpfns_gva, errs_gva;
+    CPUState *cs = CPU(cpu);
+    size_t op_sz;
+
+    if (hypercall_compat32(exit->u.hcall.longmode)) {
+        struct compat_xen_add_to_physmap_batch xatpb32;
+
+        qemu_build_assert(sizeof(struct compat_xen_add_to_physmap_batch) == 20);
+        if (kvm_copy_from_gva(cs, arg, &xatpb32, sizeof(xatpb32))) {
+            return -EFAULT;
+        }
+        xatpb.domid = xatpb32.domid;
+        xatpb.space = xatpb32.space;
+        xatpb.size = xatpb32.size;
+
+        idxs_gva = xatpb32.idxs.c;
+        gpfns_gva = xatpb32.gpfns.c;
+        errs_gva = xatpb32.errs.c;
+        op_sz = sizeof(uint32_t);
+    } else {
+        if (kvm_copy_from_gva(cs, arg, &xatpb, sizeof(xatpb))) {
+            return -EFAULT;
+        }
+        op_sz = sizeof(unsigned long);
+        idxs_gva = (unsigned long)xatpb.idxs.p;
+        gpfns_gva = (unsigned long)xatpb.gpfns.p;
+        errs_gva = (unsigned long)xatpb.errs.p;
+    }
+
+    if (xatpb.domid != DOMID_SELF && xatpb.domid != xen_domid) {
+        return -ESRCH;
+    }
+
+    /* Explicitly invalid for the batch op. Not that we implement it anyway. */
+    if (xatpb.space == XENMAPSPACE_gmfn_range) {
+        return -EINVAL;
+    }
+
+    while (xatpb.size--) {
+        unsigned long idx = 0;
+        unsigned long gpfn = 0;
+        int err;
+
+        /* For 32-bit compat this only copies the low 32 bits of each */
+        if (kvm_copy_from_gva(cs, idxs_gva, &idx, op_sz) ||
+            kvm_copy_from_gva(cs, gpfns_gva, &gpfn, op_sz)) {
+            return -EFAULT;
+        }
+        idxs_gva += op_sz;
+        gpfns_gva += op_sz;
+
+        err = add_to_physmap_one(xatpb.space, idx, gpfn);
+
+        if (kvm_copy_to_gva(cs, errs_gva, &err, sizeof(err))) {
+            return -EFAULT;
+        }
+        errs_gva += sizeof(err);
+    }
+    return 0;
+}
+
 static bool kvm_xen_hcall_memory_op(struct kvm_xen_exit *exit, X86CPU *cpu,
                                    int cmd, uint64_t arg)
 {
@@ -272,6 +337,10 @@ static bool kvm_xen_hcall_memory_op(struct kvm_xen_exit *exit, X86CPU *cpu,
         err = do_add_to_physmap(exit, cpu, arg);
         break;
 
+    case XENMEM_add_to_physmap_batch:
+        err = do_add_to_physmap_batch(exit, cpu, arg);
+        break;
+
     default:
         return false;
     }