[src/trunk]: src/sys/arch/xen/xen Pull from bouyer-xenpvh:

[bouyer <bouyer%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0d0ca24f1c2f
branches:  trunk
changeset: 931048:0d0ca24f1c2f
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Mon Apr 20 20:03:21 2020 +0000

description:
Pull from bouyer-xenpvh:
Bad news:
 * 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)

So restore grant table v1 for !XENPV

diffstat:

 sys/arch/xen/xen/xengnt.c |  116 +++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 104 insertions(+), 12 deletions(-)

diffs (242 lines):

diff -r 54802125a49c -r 0d0ca24f1c2f sys/arch/xen/xen/xengnt.c
--- a/sys/arch/xen/xen/xengnt.c Mon Apr 20 19:29:09 2020 +0000
+++ b/sys/arch/xen/xen/xengnt.c Mon Apr 20 20:03:21 2020 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: xengnt.c,v 1.35 2020/04/14 07:41:05 jdolecek Exp $      */
+/*      $NetBSD: xengnt.c,v 1.36 2020/04/20 20:03:21 bouyer Exp $      */
 
 /*
  * Copyright (c) 2006 Manuel Bouyer.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.35 2020/04/14 07:41:05 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xengnt.c,v 1.36 2020/04/20 20:03:21 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 */