@@ -1,4 +1,4 @@
-/* $NetBSD: xengnt.c,v 1.29.2.1 2020/04/20 11:29:01 bouyer Exp $ */
+/* $NetBSD: xengnt.c,v 1.29.2.2 2020/04/20 19:42:10 bouyer Exp $ */
/*
* Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.29.2.1 2020/04/20 11:29:01 bouyer Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.29.2.2 2020/04/20 19:42:10 bouyer Exp $");
#include <sys/types.h>
#include <sys/param.h>
@@ -42,6 +42,18 @@
#include <xen/xen.h>
#include <xen/granttables.h>
+#include "opt_xen.h"
+
+/*
+ * grant table v2 is not supported for HVM guests on 4.11 at last.
+ * see xen/arch/x86/hvm/hypercall.c in Xen sources (missing
+ * GNTTABOP_get_status_frames)
+ */
+
+#ifdef XENPV
+#define USE_GRANT_V2
+#endif
+
/* #define XENDEBUG */
#ifdef XENDEBUG
#define DPRINTF(x) printf x
@@ -49,9 +61,6 @@
#define DPRINTF(x)
#endif
-#define NR_GRANT_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(grant_entry_v2_t))
-#define NR_GRANT_STATUS_PER_PAGE (PAGE_SIZE / sizeof(grant_status_t))
-
/* External tools reserve first few grant table entries. */
#define NR_RESERVED_ENTRIES 8
@@ -59,8 +68,6 @@
int gnt_nr_grant_frames;
/* Maximum number of frames that can make up the grant table */
int gnt_max_grant_frames;
-/* Number of grant status frames */
-int gnt_status_frames;
/* table of free grant entries */
grant_ref_t *gnt_entries;
@@ -70,8 +77,19 @@
#define XENGNT_NO_ENTRY 0xffffffff
/* VM address of the grant table */
+#ifdef USE_GRANT_V2
+#define NR_GRANT_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(grant_entry_v2_t))
+#define NR_GRANT_STATUS_PER_PAGE (PAGE_SIZE / sizeof(grant_status_t))
+
grant_entry_v2_t *grant_table;
+/* Number of grant status frames */
+int gnt_status_frames;
+
grant_status_t *grant_status;
+#else /* USE_GRANT_V2 */
+#define NR_GRANT_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(grant_entry_v1_t))
+grant_entry_v1_t *grant_table;
+#endif /* USE_GRANT_V2 */
kmutex_t grant_lock;
static grant_ref_t xengnt_get_entry(void);
@@ -83,7 +101,6 @@
xengnt_init(void)
{
struct gnttab_query_size query;
- struct gnttab_set_version gntversion;
int rc;
int nr_grant_entries;
int i;
@@ -100,10 +117,14 @@
*/
gnt_nr_grant_frames = gnt_max_grant_frames;
+
+#ifdef USE_GRANT_V2
+ struct gnttab_set_version gntversion;
gntversion.version = 2;
rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gntversion, 1);
if (rc < 0 || gntversion.version != 2)
panic("GNTTABOP_set_version 2 failed %d", rc);
+#endif /* USE_GRANT_V2 */
nr_grant_entries =
gnt_max_grant_frames * NR_GRANT_ENTRIES_PER_PAGE;
@@ -118,12 +139,14 @@
for (i = 0; i <= nr_grant_entries; i++)
gnt_entries[i] = XENGNT_NO_ENTRY;
+#ifdef USE_GRANT_V2
gnt_status_frames =
round_page(nr_grant_entries * sizeof(grant_status_t)) / PAGE_SIZE;
grant_status = (void *)uvm_km_alloc(kernel_map,
gnt_status_frames * PAGE_SIZE, 0, UVM_KMF_VAONLY);
if (grant_status == NULL)
panic("xengnt_init() status no VM space");
+#endif /* USE_GRANT_V2 */
mutex_init(&grant_lock, MUTEX_DEFAULT, IPL_VM);
@@ -171,8 +194,10 @@
/* Remove virtual => machine mapping for grant table */
pmap_kremove((vaddr_t)grant_table, gnt_nr_grant_frames * PAGE_SIZE);
+#ifdef USE_GRANT_V2
/* Remove virtual => machine mapping for status table */
pmap_kremove((vaddr_t)grant_status, gnt_status_frames * PAGE_SIZE);
+#endif
pmap_update(pmap_kernel());
mutex_exit(&grant_lock);
@@ -185,9 +210,11 @@
static int
xengnt_map_status(void)
{
+#ifdef USE_GRANT_V2
gnttab_get_status_frames_t getstatus;
uint64_t *pages;
size_t sz;
+ int err;
KASSERT(mutex_owned(&grant_lock));
@@ -204,9 +231,9 @@
* get the status frames, and return the list of their virtual
* addresses in 'pages'
*/
- if (HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
- &getstatus, 1) != 0)
- panic("%s: get_status_frames failed", __func__);
+ if ((err = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
+ &getstatus, 1)) != 0)
+ panic("%s: get_status_frames failed: %d", __func__, err);
if (getstatus.status != GNTST_okay) {
aprint_error("%s: get_status_frames returned %d\n",
__func__, getstatus.status);
@@ -227,6 +254,7 @@
kmem_free(pages, sz);
+#endif /* USE_GRANT_V2 */
return 0;
}
@@ -370,6 +398,7 @@
mutex_exit(&grant_lock);
}
+#ifdef USE_GRANT_V2
int
xengnt_grant_access(domid_t dom, paddr_t ma, int ro, grant_ref_t *entryp)
{
@@ -414,7 +443,6 @@
*/
__insn_barrier();
}
-
xengnt_free_entry(entry);
}
@@ -423,3 +451,67 @@
{
return grant_status[entry] & (GTF_reading|GTF_writing);
}
+#else /* USE_GRANT_V2 */
+
+int
+xengnt_grant_access(domid_t dom, paddr_t ma, int ro, grant_ref_t *entryp)
+{
+ mutex_enter(&grant_lock);
+
+ *entryp = xengnt_get_entry();
+ if (__predict_false(*entryp == XENGNT_NO_ENTRY)) {
+ mutex_exit(&grant_lock);
+ return ENOMEM;
+ }
+
+ grant_table[*entryp].frame = ma >> PAGE_SHIFT;
+ grant_table[*entryp].domid = dom;
+ /*
+ * ensure that the above values reach global visibility
+ * before permitting frame's access (done when we set flags)
+ */
+ xen_rmb();
+ grant_table[*entryp].flags =
+ GTF_permit_access | (ro ? GTF_readonly : 0);
+ mutex_exit(&grant_lock);
+ return 0;
+}
+
+
+static inline uint16_t
+xen_atomic_cmpxchg16(volatile uint16_t *ptr, uint16_t val, uint16_t newval)
+{
+ unsigned long result;
+
+ __asm volatile(__LOCK_PREFIX
+ "cmpxchgw %w1,%2"
+ :"=a" (result)
+ :"q"(newval), "m" (*ptr), "0" (val)
+ :"memory");
+
+ return result;
+}
+
+void
+xengnt_revoke_access(grant_ref_t entry)
+{
+
+ uint16_t flags, nflags;
+
+ nflags = grant_table[entry].flags;
+
+ do {
+ if ((flags = nflags) & (GTF_reading|GTF_writing))
+ panic("xengnt_revoke_access: still in use");
+ nflags = xen_atomic_cmpxchg16(&grant_table[entry].flags,
+ flags, 0);
+ } while (nflags != flags);
+ xengnt_free_entry(entry);
+}
+
+int
+xengnt_status(grant_ref_t entry)
+{
+ return (grant_table[entry].flags & (GTF_reading|GTF_writing));
+}
+#endif /* USE_GRANT_V2 */