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authorgibbs <gibbs@FreeBSD.org>2010-10-19 20:53:30 +0000
committergibbs <gibbs@FreeBSD.org>2010-10-19 20:53:30 +0000
commit831bbfaf753dc145ab80d1807336d4fb9ef8dffe (patch)
tree485da62e94858a8622baf0c76026e92d1a0b6c56 /sys/xen/gnttab.c
parente8fd2e51b37c5299a1a7540aca2ce0a3a2765672 (diff)
downloadFreeBSD-src-831bbfaf753dc145ab80d1807336d4fb9ef8dffe.zip
FreeBSD-src-831bbfaf753dc145ab80d1807336d4fb9ef8dffe.tar.gz
Improve the Xen para-virtualized device infrastructure of FreeBSD:
o Add support for backend devices (e.g. blkback) o Implement extensions to the Xen para-virtualized block API to allow for larger and more outstanding I/Os. o Import a completely rewritten block back driver with support for fronting I/O to both raw devices and files. o General cleanup and documentation of the XenBus and XenStore support code. o Robustness and performance updates for the block front driver. o Fixes to the netfront driver. Sponsored by: Spectra Logic Corporation sys/xen/xenbus/init.txt: Deleted: This file explains the Linux method for XenBus device enumeration and thus does not apply to FreeBSD's NewBus approach. sys/xen/xenbus/xenbus_probe_backend.c: Deleted: Linux version of backend XenBus service routines. It was never ported to FreeBSD. See xenbusb.c, xenbusb_if.m, xenbusb_front.c xenbusb_back.c for details of FreeBSD's XenBus support. sys/xen/xenbus/xenbusvar.h: sys/xen/xenbus/xenbus_xs.c: sys/xen/xenbus/xenbus_comms.c: sys/xen/xenbus/xenbus_comms.h: sys/xen/xenstore/xenstorevar.h: sys/xen/xenstore/xenstore.c: Split XenStore into its own tree. XenBus is a software layer built on top of XenStore. The old arrangement and the naming of some structures and functions blurred these lines making it difficult to discern what services are provided by which layer and at what times these services are available (e.g. during system startup and shutdown). sys/xen/xenbus/xenbus_client.c: sys/xen/xenbus/xenbus.c: sys/xen/xenbus/xenbus_probe.c: sys/xen/xenbus/xenbusb.c: sys/xen/xenbus/xenbusb.h: Split up XenBus code into methods available for use by client drivers (xenbus.c) and code used by the XenBus "bus code" to enumerate, attach, detach, and service bus drivers. sys/xen/reboot.c: sys/dev/xen/control/control.c: Add a XenBus front driver for handling shutdown, reboot, suspend, and resume events published in the XenStore. Move all PV suspend/reboot support from reboot.c into this driver. sys/xen/blkif.h: New file from Xen vendor with macros and structures used by a block back driver to service requests from a VM running a different ABI (e.g. amd64 back with i386 front). sys/conf/files: Adjust kernel build spec for new XenBus/XenStore layout and added Xen functionality. sys/dev/xen/balloon/balloon.c: sys/dev/xen/netfront/netfront.c: sys/dev/xen/blkfront/blkfront.c: sys/xen/xenbus/... sys/xen/xenstore/... o Rename XenStore APIs and structures from xenbus_* to xs_*. o Adjust to use of M_XENBUS and M_XENSTORE malloc types for allocation of objects returned by these APIs. o Adjust for changes in the bus interface for Xen drivers. sys/xen/xenbus/... sys/xen/xenstore/... Add Doxygen comments for these interfaces and the code that implements them. sys/dev/xen/blkback/blkback.c: o Rewrite the Block Back driver to attach properly via newbus, operate correctly in both PV and HVM mode regardless of domain (e.g. can be in a DOM other than 0), and to deal with the latest metadata available in XenStore for block devices. o Allow users to specify a file as a backend to blkback, in addition to character devices. Use the namei lookup of the backend path to automatically configure, based on file type, the appropriate backend method. The current implementation is limited to a single outstanding I/O at a time to file backed storage. sys/dev/xen/blkback/blkback.c: sys/xen/interface/io/blkif.h: sys/xen/blkif.h: sys/dev/xen/blkfront/blkfront.c: sys/dev/xen/blkfront/block.h: Extend the Xen blkif API: Negotiable request size and number of requests. This change extends the information recorded in the XenStore allowing block front/back devices to negotiate for optimal I/O parameters. This has been achieved without sacrificing backward compatibility with drivers that are unaware of these protocol enhancements. The extensions center around the connection protocol which now includes these additions: o The back-end device publishes its maximum supported values for, request I/O size, the number of page segments that can be associated with a request, the maximum number of requests that can be concurrently active, and the maximum number of pages that can be in the shared request ring. These values are published before the back-end enters the XenbusStateInitWait state. o The front-end waits for the back-end to enter either the InitWait or Initialize state. At this point, the front end limits it's own capabilities to the lesser of the values it finds published by the backend, it's own maximums, or, should any back-end data be missing in the store, the values supported by the original protocol. It then initializes it's internal data structures including allocation of the shared ring, publishes its maximum capabilities to the XenStore and transitions to the Initialized state. o The back-end waits for the front-end to enter the Initalized state. At this point, the back end limits it's own capabilities to the lesser of the values it finds published by the frontend, it's own maximums, or, should any front-end data be missing in the store, the values supported by the original protocol. It then initializes it's internal data structures, attaches to the shared ring and transitions to the Connected state. o The front-end waits for the back-end to enter the Connnected state, transitions itself to the connected state, and can commence I/O. Although an updated front-end driver must be aware of the back-end's InitWait state, the back-end has been coded such that it can tolerate a front-end that skips this step and transitions directly to the Initialized state without waiting for the back-end. sys/xen/interface/io/blkif.h: o Increase BLKIF_MAX_SEGMENTS_PER_REQUEST to 255. This is the maximum number possible without changing the blkif request header structure (nr_segs is a uint8_t). o Add two new constants: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK, and BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK. These respectively indicate the number of segments that can fit in the first ring-buffer entry of a request, and for each subsequent (sg element only) ring-buffer entry associated with the "header" ring-buffer entry of the request. o Add the blkif_request_segment_t typedef for segment elements. o Add the BLKRING_GET_SG_REQUEST() macro which wraps the RING_GET_REQUEST() macro and returns a properly cast pointer to an array of blkif_request_segment_ts. o Add the BLKIF_SEGS_TO_BLOCKS() macro which calculates the number of ring entries that will be consumed by a blkif request with the given number of segments. sys/xen/blkif.h: o Update for changes in interface/io/blkif.h macros. o Update the BLKIF_MAX_RING_REQUESTS() macro to take the ring size as an argument to allow this calculation on multi-page rings. o Add a companion macro to BLKIF_MAX_RING_REQUESTS(), BLKIF_RING_PAGES(). This macro determines the number of ring pages required in order to support a ring with the supplied number of request blocks. sys/dev/xen/blkback/blkback.c: sys/dev/xen/blkfront/blkfront.c: sys/dev/xen/blkfront/block.h: o Negotiate with the other-end with the following limits: Reqeust Size: MAXPHYS Max Segments: (MAXPHYS/PAGE_SIZE) + 1 Max Requests: 256 Max Ring Pages: Sufficient to support Max Requests with Max Segments. o Dynamically allocate request pools and segemnts-per-request. o Update ring allocation/attachment code to support a multi-page shared ring. o Update routines that access the shared ring to handle multi-block requests. sys/dev/xen/blkfront/blkfront.c: o Track blkfront allocations in a blkfront driver specific malloc pool. o Strip out XenStore transaction retry logic in the connection code. Transactions only need to be used when the update to multiple XenStore nodes must be atomic. That is not the case here. o Fully disable blkif_resume() until it can be fixed properly (it didn't work before this change). o Destroy bus-dma objects during device instance tear-down. o Properly handle backend devices with powef-of-2 sector sizes larger than 512b. sys/dev/xen/blkback/blkback.c: Advertise support for and implement the BLKIF_OP_WRITE_BARRIER and BLKIF_OP_FLUSH_DISKCACHE blkif opcodes using BIO_FLUSH and the BIO_ORDERED attribute of bios. sys/dev/xen/blkfront/blkfront.c: sys/dev/xen/blkfront/block.h: Fix various bugs in blkfront. o gnttab_alloc_grant_references() returns 0 for success and non-zero for failure. The check for < 0 is a leftover Linuxism. o When we negotiate with blkback and have to reduce some of our capabilities, print out the original and reduced capability before changing the local capability. So the user now gets the correct information. o Fix blkif_restart_queue_callback() formatting. Make sure we hold the mutex in that function before calling xb_startio(). o Fix a couple of KASSERT()s. o Fix a check in the xb_remove_* macro to be a little more specific. sys/xen/gnttab.h: sys/xen/gnttab.c: Define GNTTAB_LIST_END publicly as GRANT_REF_INVALID. sys/dev/xen/netfront/netfront.c: Use GRANT_REF_INVALID instead of driver private definitions of the same constant. sys/xen/gnttab.h: sys/xen/gnttab.c: Add the gnttab_end_foreign_access_references() API. This API allows a client to batch the release of an array of grant references, instead of coding a private for loop. The implementation takes advantage of this batching to reduce lock overhead to one acquisition and release per-batch instead of per-freed grant reference. While here, reduce the duration the gnttab_list_lock is held during gnttab_free_grant_references() operations. The search to find the tail of the incoming free list does not rely on global state and so can be performed without holding the lock. sys/dev/xen/xenpci/evtchn.c: sys/dev/xen/evtchn/evtchn.c: sys/xen/xen_intr.h: o Implement the bind_interdomain_evtchn_to_irqhandler API for HVM mode. This allows an HVM domain to serve back end devices to other domains. This API is already implemented for PV mode. o Synchronize the API between HVM and PV. sys/dev/xen/xenpci/xenpci.c: o Scan the full region of CPUID space in which the Xen VMM interface may be implemented. On systems using SuSE as a Dom0 where the Viridian API is also exported, the VMM interface is above the region we used to search. o Pass through bus_alloc_resource() calls so that XenBus drivers attaching on an HVM system can allocate unused physical address space from the nexus. The block back driver makes use of this facility. sys/i386/xen/xen_machdep.c: Use the correct type for accessing the statically mapped xenstore metadata. sys/xen/interface/hvm/params.h: sys/xen/xenstore/xenstore.c: Move hvm_get_parameter() to the correct global header file instead of as a private method to the XenStore. sys/xen/interface/io/protocols.h: Sync with vendor. sys/xeninterface/io/ring.h: Add macro for calculating the number of ring pages needed for an N deep ring. To avoid duplication within the macros, create and use the new __RING_HEADER_SIZE() macro. This macro calculates the size of the ring book keeping struct (producer/consumer indexes, etc.) that resides at the head of the ring. Add the __RING_PAGES() macro which calculates the number of shared ring pages required to support a ring with the given number of requests. These APIs are used to support the multi-page ring version of the Xen block API. sys/xeninterface/io/xenbus.h: Add Comments. sys/xen/xenbus/... o Refactor the FreeBSD XenBus support code to allow for both front and backend device attachments. o Make use of new config_intr_hook capabilities to allow front and back devices to be probed/attached in parallel. o Fix bugs in probe/attach state machine that could cause the system to hang when confronted with a failure either in the local domain or in a remote domain to which one of our driver instances is attaching. o Publish all required state to the XenStore on device detach and failure. The majority of the missing functionality was for serving as a back end since the typical "hot-plug" scripts in Dom0 don't handle the case of cleaning up for a "service domain" that is not itself. o Add dynamic sysctl nodes exposing the generic ivars of XenBus devices. o Add doxygen style comments to the majority of the code. o Cleanup types, formatting, etc. sys/xen/xenbus/xenbusb.c: Common code used by both front and back XenBus busses. sys/xen/xenbus/xenbusb_if.m: Method definitions for a XenBus bus. sys/xen/xenbus/xenbusb_front.c: sys/xen/xenbus/xenbusb_back.c: XenBus bus specialization for front and back devices. MFC after: 1 month
Diffstat (limited to 'sys/xen/gnttab.c')
-rw-r--r--sys/xen/gnttab.c80
1 files changed, 58 insertions, 22 deletions
diff --git a/sys/xen/gnttab.c b/sys/xen/gnttab.c
index ae44e8f..4ece182 100644
--- a/sys/xen/gnttab.c
+++ b/sys/xen/gnttab.c
@@ -42,7 +42,6 @@ __FBSDID("$FreeBSD$");
/* External tools reserve first few grant table entries. */
#define NR_RESERVED_ENTRIES 8
-#define GNTTAB_LIST_END 0xffffffff
#define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(grant_entry_t))
static grant_ref_t **gnttab_list;
@@ -66,7 +65,7 @@ get_free_entries(int count, int *entries)
{
int ref, error;
grant_ref_t head;
-
+
mtx_lock(&gnttab_list_lock);
if ((gnttab_free_count < count) &&
((error = gnttab_expand(count - gnttab_free_count)) != 0)) {
@@ -79,7 +78,7 @@ get_free_entries(int count, int *entries)
head = gnttab_entry(head);
gnttab_free_head = gnttab_entry(head);
gnttab_entry(head) = GNTTAB_LIST_END;
- mtx_unlock(&gnttab_list_lock);
+ mtx_unlock(&gnttab_list_lock);
*entries = ref;
return (0);
@@ -122,7 +121,7 @@ put_free_entry(grant_ref_t ref)
gnttab_free_head = ref;
gnttab_free_count++;
check_free_callbacks();
- mtx_unlock(&gnttab_list_lock);
+ mtx_unlock(&gnttab_list_lock);
}
/*
@@ -136,7 +135,7 @@ gnttab_grant_foreign_access(domid_t domid, unsigned long frame, int readonly,
int error, ref;
error = get_free_entries(1, &ref);
-
+
if (unlikely(error))
return (error);
@@ -166,9 +165,9 @@ int
gnttab_query_foreign_access(grant_ref_t ref)
{
uint16_t nflags;
-
+
nflags = shared[ref].flags;
-
+
return (nflags & (GTF_reading|GTF_writing));
}
@@ -180,7 +179,7 @@ gnttab_end_foreign_access_ref(grant_ref_t ref)
nflags = shared[ref].flags;
do {
if ( (flags = nflags) & (GTF_reading|GTF_writing) ) {
- printf("WARNING: g.e. still in use!\n");
+ printf("%s: WARNING: g.e. still in use!\n", __func__);
return (0);
}
} while ((nflags = synch_cmpxchg(&shared[ref].flags, flags, 0)) !=
@@ -201,7 +200,44 @@ gnttab_end_foreign_access(grant_ref_t ref, void *page)
else {
/* XXX This needs to be fixed so that the ref and page are
placed on a list to be freed up later. */
- printf("WARNING: leaking g.e. and page still in use!\n");
+ printf("%s: WARNING: leaking g.e. and page still in use!\n",
+ __func__);
+ }
+}
+
+void
+gnttab_end_foreign_access_references(u_int count, grant_ref_t *refs)
+{
+ grant_ref_t *last_ref;
+ grant_ref_t head;
+ grant_ref_t tail;
+
+ head = GNTTAB_LIST_END;
+ tail = *refs;
+ last_ref = refs + count;
+ while (refs != last_ref) {
+
+ if (gnttab_end_foreign_access_ref(*refs)) {
+ gnttab_entry(*refs) = head;
+ head = *refs;
+ } else {
+ /*
+ * XXX This needs to be fixed so that the ref
+ * is placed on a list to be freed up later.
+ */
+ printf("%s: WARNING: leaking g.e. still in use!\n",
+ __func__);
+ count--;
+ }
+ refs++;
+ }
+
+ if (count != 0) {
+ mtx_lock(&gnttab_list_lock);
+ gnttab_free_count += count;
+ gnttab_entry(tail) = gnttab_free_head;
+ gnttab_free_head = head;
+ mtx_unlock(&gnttab_list_lock);
}
}
@@ -216,7 +252,7 @@ gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn,
return (error);
gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
-
+
*result = ref;
return (0);
}
@@ -282,16 +318,16 @@ gnttab_free_grant_references(grant_ref_t head)
{
grant_ref_t ref;
int count = 1;
-
+
if (head == GNTTAB_LIST_END)
return;
-
- mtx_lock(&gnttab_list_lock);
+
ref = head;
while (gnttab_entry(ref) != GNTTAB_LIST_END) {
ref = gnttab_entry(ref);
count++;
}
+ mtx_lock(&gnttab_list_lock);
gnttab_entry(ref) = gnttab_free_head;
gnttab_free_head = head;
gnttab_free_count += count;
@@ -403,7 +439,7 @@ grow_gnttab_list(unsigned int more_frames)
check_free_callbacks();
return (0);
-
+
grow_nomem:
for ( ; i >= nr_grant_frames; i--)
free(gnttab_list[i], M_DEVBUF);
@@ -490,7 +526,7 @@ gnttab_map(unsigned int start_idx, unsigned int end_idx)
if (shared == NULL) {
vm_offset_t area;
-
+
area = kmem_alloc_nofault(kernel_map,
PAGE_SIZE * max_nr_grant_frames());
KASSERT(area, ("can't allocate VM space for grant table"));
@@ -502,7 +538,7 @@ gnttab_map(unsigned int start_idx, unsigned int end_idx)
((vm_paddr_t)frames[i]) << PAGE_SHIFT | PG_RW | PG_V);
free(frames, M_DEVBUF);
-
+
return (0);
}
@@ -517,7 +553,7 @@ gnttab_resume(void)
int
gnttab_suspend(void)
-{
+{
int i;
for (i = 0; i < nr_grant_frames; i++)
@@ -532,7 +568,8 @@ gnttab_suspend(void)
static vm_paddr_t resume_frames;
-static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
+static int
+gnttab_map(unsigned int start_idx, unsigned int end_idx)
{
struct xen_add_to_physmap xatp;
unsigned int i = end_idx;
@@ -552,7 +589,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
if (shared == NULL) {
vm_offset_t area;
-
+
area = kmem_alloc_nofault(kernel_map,
PAGE_SIZE * max_nr_grant_frames());
KASSERT(area, ("can't allocate VM space for grant table"));
@@ -643,10 +680,10 @@ gnttab_init()
if (gnttab_list[i] == NULL)
goto ini_nomem;
}
-
+
if (gnttab_resume())
return (ENODEV);
-
+
nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME;
for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
@@ -670,4 +707,3 @@ ini_nomem:
}
MTX_SYSINIT(gnttab, &gnttab_list_lock, "GNTTAB LOCK", MTX_DEF);
-//SYSINIT(gnttab, SI_SUB_PSEUDO, SI_ORDER_FIRST, gnttab_init, NULL);
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