On Fri, Oct 03, 2014 at 06:47:41PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Add MIG_RPCOMM_REQPAGES command on Return path for the postcopy
> destination to request a page from the source.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> include/migration/migration.h | 3 ++
> migration.c | 74
> +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 77 insertions(+)
>
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index cdd0e56..5e0d30d 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -45,6 +45,7 @@ enum mig_rpcomm_cmd {
> MIG_RPCOMM_INVALID = 0, /* Must be 0 */
> MIG_RPCOMM_SHUT, /* sibling will not send any more RP messages */
> MIG_RPCOMM_ACK, /* data (seq: be32 ) */
> + MIG_RPCOMM_REQPAGES, /* data (start: be64, len: be64) */
> MIG_RPCOMM_AFTERLASTVALID
> };
>
> @@ -250,6 +251,8 @@ void migrate_send_rp_shut(MigrationIncomingState *mis,
> uint32_t value);
> void migrate_send_rp_ack(MigrationIncomingState *mis,
> uint32_t value);
> +void migrate_send_rp_reqpages(MigrationIncomingState *mis, const char*
> rbname,
> + ram_addr_t start, ram_addr_t len);
>
>
> void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
> diff --git a/migration.c b/migration.c
> index 1731017..cfdaa52 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -144,6 +144,38 @@ void migrate_send_rp_ack(MigrationIncomingState *mis,
> migrate_send_rp_message(mis, MIG_RPCOMM_ACK, 4, (uint8_t *)&buf);
> }
>
> +/* Request a range of pages from the source VM at the given
> + * start address.
> + * rbname: Name of the RAMBlock to request the page in, if NULL it's the
> same
> + * as the last request (a name must have been given previously)
> + * Start: Address offset within the RB
> + * Len: Length in bytes required - must be a multiple of pagesize
> + */
> +void migrate_send_rp_reqpages(MigrationIncomingState *mis, const char
> *rbname,
> + ram_addr_t start, ram_addr_t len)
> +{
> + uint8_t bufc[16+1+255]; /* start (8 byte), len (8 byte), rbname upto 256
> */
> + uint64_t *buf64 = (uint64_t *)bufc;
> + size_t msglen = 16; /* start + len */
> +
> + assert(!(len & 1));
> + if (rbname) {
> + int rbname_len = strlen(rbname);
> + assert(rbname_len < 256);
> +
> + len |= 1; /* Flag to say we've got a name */
> + bufc[msglen++] = rbname_len;
> + memcpy(bufc + msglen, rbname, rbname_len);
> + msglen += rbname_len;
> + }
> +
> + buf64[0] = (uint64_t)start;
> + buf64[0] = cpu_to_be64(buf64[0]);
I think this would be clearer as well as less verbose, as just:
buf64[0] = cpu_to_be64(start);
> + buf64[1] = (uint64_t)len;
> + buf64[1] = cpu_to_be64(buf64[1]);
> + migrate_send_rp_message(mis, MIG_RPCOMM_REQPAGES, msglen, bufc);
> +}
> +
> void qemu_start_incoming_migration(const char *uri, Error **errp)
> {
> const char *p;
> @@ -784,6 +816,17 @@ static void source_return_path_bad(MigrationState *s)
> }
>
> /*
> + * Process a request for pages received on the return path,
> + * We're allowed to send more than requested (e.g. to round to our page size)
> + * and we don't need to send pages that have already been sent.
> + */
> +static void migrate_handle_rp_reqpages(MigrationState *ms, const char*
> rbname,
> + ram_addr_t start, ram_addr_t len)
> +{
> + DPRINTF("migrate_handle_rp_reqpages: at %zx for len %zx", start, len);
> +}
> +
> +/*
> * Handles messages sent on the return path towards the source VM
> *
> */
> @@ -795,6 +838,8 @@ static void *source_return_path_thread(void *opaque)
> const int max_len = 512;
> uint8_t buf[max_len];
> uint32_t tmp32;
> + uint64_t tmp64a, tmp64b;
Hrm.. calling everything "tmp*" doesn't help readability.
> + char *tmpstr;
> int res;
>
> DPRINTF("RP: %s entry", __func__);
> @@ -810,6 +855,11 @@ static void *source_return_path_thread(void *opaque)
> expected_len = 4;
> break;
>
> + case MIG_RPCOMM_REQPAGES:
> + /* 16 byte start/len _possibly_ plus an id str */
> + expected_len = 16 + 256;
> + break;
> +
> default:
> error_report("RP: Received invalid cmd 0x%04x length 0x%04x",
> header_com, header_len);
> @@ -857,6 +907,30 @@ static void *source_return_path_thread(void *opaque)
> atomic_xchg(&ms->rp_state.latest_ack, tmp32);
> break;
>
> + case MIG_RPCOMM_REQPAGES:
> + tmp64a = be64_to_cpup((uint64_t *)buf); /* Start */
> + tmp64b = be64_to_cpup(((uint64_t *)buf)+1); /* Len */
> + tmpstr = NULL;
> + if (tmp64b & 1) {
> + tmp64b -= 1; /* Remove the flag */
> + /* Now we expect an idstr */
> + tmp32 = buf[16]; /* Length of the following idstr */
> + tmpstr = (char *)&buf[17];
> + buf[17+tmp32] = '\0';
> + expected_len = 16+1+tmp32;
> + } else {
> + expected_len = 16;
> + }
> + if (header_len != expected_len) {
> + error_report("RP: Received ReqPage with length %d expecting
> %d",
> + header_len, expected_len);
> + source_return_path_bad(ms);
> + }
> + migrate_handle_rp_reqpages(ms, tmpstr,
> + (ram_addr_t)tmp64a,
> + (ram_addr_t)tmp64b);
> + break;
> +
> default:
> /* This shouldn't happen because we should catch this above */
> DPRINTF("RP: Bad header_com in dispatch");
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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