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hw/s390x/s390-skeys: use memory mapping to detect which storage keys to migrate 

Let's use the guest_phys_blocks API to get physical memory regions
that are well defined inside our physical address space and migrate the
storage keys of these.

This is a preparation for having memory besides initial ram defined in
the guest physical address space, for example, via memory devices. We
get rid of the ms->ram_size dependency.

Please note that we will usually have very little (--> 1) physical
ranges. With virtio-mem might have significantly more ranges in the
future. If that turns out to be a problem (e.g., total memory
footprint of the list), we could look into a memory mapping
API that avoids creation of a list and instead triggers a callback for
each range.

Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210903155514.44772-10-david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
David Hildenbrand 2021-09-03 17:55:10 +02:00 committed by Thomas Huth
parent 380ac2bcce
commit 67db1306a2
1 changed files with 41 additions and 25 deletions
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66
hw/s390x/s390-skeys.c
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@ -17,6 +17,7 @@
#include "qapi/qapi-commands-misc-target.h"
#include "qapi/qmp/qdict.h"
#include "qemu/error-report.h"
#include "sysemu/memory_mapping.h"
#include "sysemu/kvm.h"
#include "migration/qemu-file-types.h"
#include "migration/register.h"
@ -257,10 +258,9 @@ static void s390_storage_keys_save(QEMUFile *f, void *opaque)
{
S390SKeysState *ss = S390_SKEYS(opaque);
S390SKeysClass *skeyclass = S390_SKEYS_GET_CLASS(ss);
MachineState *ms = MACHINE(qdev_get_machine());
uint64_t pages_left = ms->ram_size / TARGET_PAGE_SIZE;
uint64_t read_count, eos = S390_SKEYS_SAVE_FLAG_EOS;
vaddr cur_gfn = 0;
GuestPhysBlockList guest_phys_blocks;
GuestPhysBlock *block;
uint64_t pages, gfn;
int error = 0;
uint8_t *buf;
@ -274,36 +274,52 @@ static void s390_storage_keys_save(QEMUFile *f, void *opaque)
goto end_stream;
}
/* We only support initial memory. Standby memory is not handled yet. */
qemu_put_be64(f, (cur_gfn * TARGET_PAGE_SIZE) | S390_SKEYS_SAVE_FLAG_SKEYS);
qemu_put_be64(f, pages_left);
guest_phys_blocks_init(&guest_phys_blocks);
guest_phys_blocks_append(&guest_phys_blocks);
while (pages_left) {
read_count = MIN(pages_left, S390_SKEYS_BUFFER_SIZE);
/* Send each contiguous physical memory range separately. */
QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
assert(QEMU_IS_ALIGNED(block->target_start, TARGET_PAGE_SIZE));
assert(QEMU_IS_ALIGNED(block->target_end, TARGET_PAGE_SIZE));
if (!error) {
error = skeyclass->get_skeys(ss, cur_gfn, read_count, buf);
if (error) {
/*
* If error: we want to fill the stream with valid data instead
* of stopping early so we pad the stream with 0x00 values and
* use S390_SKEYS_SAVE_FLAG_ERROR to indicate failure to the
* reading side.
*/
error_report("S390_GET_KEYS error %d", error);
memset(buf, 0, S390_SKEYS_BUFFER_SIZE);
eos = S390_SKEYS_SAVE_FLAG_ERROR;
gfn = block->target_start / TARGET_PAGE_SIZE;
pages = (block->target_end - block->target_start) / TARGET_PAGE_SIZE;
qemu_put_be64(f, block->target_start | S390_SKEYS_SAVE_FLAG_SKEYS);
qemu_put_be64(f, pages);
while (pages) {
const uint64_t cur_pages = MIN(pages, S390_SKEYS_BUFFER_SIZE);
if (!error) {
error = skeyclass->get_skeys(ss, gfn, cur_pages, buf);
if (error) {
/*
* Create a valid stream with all 0x00 and indicate
* S390_SKEYS_SAVE_FLAG_ERROR to the destination.
*/
error_report("S390_GET_KEYS error %d", error);
memset(buf, 0, S390_SKEYS_BUFFER_SIZE);
}
}
qemu_put_buffer(f, buf, cur_pages);
gfn += cur_pages;
pages -= cur_pages;
}
qemu_put_buffer(f, buf, read_count);
cur_gfn += read_count;
pages_left -= read_count;
if (error) {
break;
}
}
guest_phys_blocks_free(&guest_phys_blocks);
g_free(buf);
end_stream:
qemu_put_be64(f, eos);
if (error) {
qemu_put_be64(f, S390_SKEYS_SAVE_FLAG_ERROR);
} else {
qemu_put_be64(f, S390_SKEYS_SAVE_FLAG_EOS);
}
}
static int s390_storage_keys_load(QEMUFile *f, void *opaque, int version_id)