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Re: [Qemu-devel] [RFC PATCH v2 15/16] Wire in BER visitors
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 15/16] Wire in BER visitors |
Date: |
Wed, 7 May 2014 11:08:03 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
* Michael S. Tsirkin (address@hidden) wrote:
> On Wed, Apr 23, 2014 at 05:37:48PM +0100, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > BER output visitor to be selected with env
> > BER input visitor recognized by file header
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> > include/migration/migration.h | 2 +
> > savevm.c | 105
> > +++++++++++++++++++++++++++++++-----------
> > 2 files changed, 80 insertions(+), 27 deletions(-)
> >
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index 8111125..5d500ec 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -27,6 +27,8 @@
> > #define QEMU_VM_FILE_VERSION_COMPAT 0x00000002
> > #define QEMU_VM_FILE_VERSION 0x00000003
> >
> > +#define QEMU_VM_BER_FILE_MAGIC 0x7fcdc551
> > +
>
> Where does this come from? I presume this matches
> something in BER format?
See ber.h, this corresponds to an Application class tag with
the BER_TYPE_QEMU_FILE; from ber.h:
BER_TYPE_QEMU_FILE = 1270481, /* come out as 7f cd c5 51 - the 51 is Q
* the c5 and cd being E,M but with the top
* bit set which BER requires.
I'll add a comment pointing to that.
Dave
>
> > #define QEMU_VM_EOF 0x00
> > #define QEMU_VM_SECTION_START 0x01
> > #define QEMU_VM_SECTION_PART 0x02
> > diff --git a/savevm.c b/savevm.c
> > index 515dd77..2bbbcdc 100644
> > --- a/savevm.c
> > +++ b/savevm.c
> > @@ -24,6 +24,8 @@
> >
> > #include "config-host.h"
> > #include "qemu-common.h"
> > +#include "qapi/qemu-file-ber-output-visitor.h"
> > +#include "qapi/qemu-file-ber-input-visitor.h"
> > #include "qapi/qemu-file-binary-input-visitor.h"
> > #include "qapi/qemu-file-binary-output-visitor.h"
> > #include "hw/hw.h"
> > @@ -527,6 +529,34 @@ bool qemu_savevm_state_blocked(Error **errp)
> > return false;
> > }
> >
> > +/* Return a visitor for use on the QEMUFile; visit_destroy should be
> > + * called on it to clean it up.
> > + */
> > +static Visitor *qemu_savevm_get_visitor(QEMUFile *f)
> > +{
> > + char *formatvar = getenv("QEMUMIGFORMAT");
> > +
> > + if (formatvar && (!strcmp(formatvar, "BER"))) {
> > + QemuFileBEROutputVisitor *qfberov =
> > qemu_file_ber_output_visitor_new(f);
> > + Visitor *v = qemu_file_ber_output_get_visitor(qfberov);
> > +
> > + qemu_file_set_tmp_visitor(f, v);
> > + return v;
> > + }
> > +
> > + if (formatvar) {
> > + error_report("QEMUMIGFORMAT set to unknown value '%s'", formatvar);
> > + assert(0);
> > + }
> > +
> > + QemuFileBinOutputVisitor *qfbov = qemu_file_bin_output_visitor_new(f);
> > + Visitor *v = qemu_file_bin_output_get_visitor(qfbov);
> > +
> > + qemu_file_set_tmp_visitor(f, v);
> > +
> > + return v;
> > +}
> > +
> > void qemu_savevm_state_begin(QEMUFile *f,
> > const MigrationParams *params)
> > {
> > @@ -534,10 +564,7 @@ void qemu_savevm_state_begin(QEMUFile *f,
> > int ret;
> > Error *local_err = NULL;
> > SectionHeader sh;
> > -
> > - QemuFileBinOutputVisitor *qfbov = qemu_file_bin_output_visitor_new(f);
> > - Visitor *v = qemu_file_bin_output_get_visitor(qfbov);
> > - qemu_file_set_tmp_visitor(f, v);
> > + Visitor *v = qemu_savevm_get_visitor(f);
> >
> > trace_savevm_state_begin();
> > QTAILQ_FOREACH(se, &savevm_handlers, entry) {
> > @@ -789,13 +816,11 @@ static int qemu_savevm_state(QEMUFile *f)
> >
> > static int qemu_save_device_state(QEMUFile *f)
> > {
> > + Visitor *v = qemu_savevm_get_visitor(f);
> > SaveStateEntry *se;
> > Error *local_err;
> > SectionHeader sh;
> >
> > - QemuFileBinOutputVisitor *qfbov = qemu_file_bin_output_visitor_new(f);
> > - qemu_file_set_tmp_visitor(f, qemu_file_bin_output_get_visitor(qfbov));
> > - Visitor *v = qemu_file_bin_output_get_visitor(qfbov);
> > int32_t section_type;
> >
> > cpu_synchronize_all_states();
> > @@ -861,41 +886,65 @@ typedef struct LoadStateEntry {
> > int version_id;
> > } LoadStateEntry;
> >
> > +/* Given a just opened input QEMUFile, peak at the header and figure
> > + * out which visitor should be used for it.
> > + * Return the visitor ready for use.
> > + */
> > +static Visitor *pick_input_visitor(QEMUFile *f)
> > +{
> > + uint32_t tmp32;
> > +
> > + if (qemu_peek_buffer(f, (uint8_t *)&tmp32, 4, 0) != 4) {
> > + fprintf(stderr, "Failed to read SaveVM header word\n");
> > + return NULL;
> > + }
> > +
> > + tmp32 = be32_to_cpu(tmp32);
> > +
> > + switch (tmp32) {
> > + case QEMU_VM_FILE_MAGIC: {
> > + QemuFileBinInputVisitor *qfbiv =
> > qemu_file_bin_input_visitor_new(f);
> > + Visitor *v = qemu_file_bin_input_get_visitor(qfbiv);
> > + qemu_file_set_tmp_visitor(f, v);
> > +
> > + return v;
> > + }
> > +
> > + case QEMU_VM_BER_FILE_MAGIC: {
> > + QemuFileBERInputVisitor *qfberiv =
> > qemu_file_ber_input_visitor_new(f);
> > + Visitor *v = qemu_file_ber_input_get_visitor(qfberiv);
> > + qemu_file_set_tmp_visitor(f, v);
> > +
> > + return v;
> > + }
> > +
> > + default:
> > + fprintf(stderr, "Invalid SaveVM header (0x%x)\n", tmp32);
> > + return NULL;
> > + }
> > +}
> > +
> > int qemu_loadvm_state(QEMUFile *f)
> > {
> > QLIST_HEAD(, LoadStateEntry) loadvm_handlers =
> > QLIST_HEAD_INITIALIZER(loadvm_handlers);
> > LoadStateEntry *le, *new_le;
> > + Visitor *v;
> > Error *local_err = NULL;
> > int32_t section_type;
> > - unsigned int tmp;
> > int ret;
> >
> > if (qemu_savevm_state_blocked(NULL)) {
> > return -EINVAL;
> > }
> >
> > - tmp = qemu_get_be32(f);
> > - if (tmp != QEMU_VM_FILE_MAGIC) {
> > - return -EINVAL;
> > - }
> > -
> > - tmp = qemu_get_be32(f);
> > - if (tmp == QEMU_VM_FILE_VERSION_COMPAT) {
> > - error_report("SaveVM v2 format is obsolete and don't work
> > anymore");
> > + v = pick_input_visitor(f);
> > + if (!v) {
> > return -ENOTSUP;
> > }
> > - if (tmp != QEMU_VM_FILE_VERSION) {
> > - return -ENOTSUP;
> > - }
> > -
> > - /* TODO: Here we should be able to figure out if it's a binary file
> > - * or what and open the right type of visitor
> > - */
> > - QemuFileBinInputVisitor *qfbiv = qemu_file_bin_input_visitor_new(f);
> > - Visitor *v = qemu_file_bin_input_get_visitor(qfbiv);
> > - qemu_file_set_tmp_visitor(f, v);
> >
> > + visit_start_sequence_compat(v, "file", VISIT_SEQ_COMPAT_FILE, NULL,
> > + &local_err);
> > visit_start_sequence_compat(v, "top", VISIT_SEQ_COMPAT_BYTE0TERM,
> > NULL, &local_err);
> > while (visit_get_next_type(v, §ion_type, NULL, "section",
> > &local_err),
> > @@ -912,6 +961,7 @@ int qemu_loadvm_state(QEMUFile *f)
> > "secstart" : "secfull",
> > VISIT_SEQ_COMPAT_SECTION_HEADER, &sh, &local_err);
> > if (local_err) {
> > + error_report("%s", error_get_pretty(local_err));
> > ret = -EINVAL;
> > goto out;
> > }
> > @@ -1001,6 +1051,7 @@ out:
> > }
> >
> > visit_end_sequence_compat(v, "top", VISIT_SEQ_COMPAT_BYTE0TERM,
> > &local_err);
> > + visit_end_sequence_compat(v, "file", VISIT_SEQ_COMPAT_FILE,
> > &local_err);
> > if (local_err) {
> > error_report("%s", error_get_pretty(local_err));
> > ret = -EINVAL;
> > @@ -1010,7 +1061,7 @@ out:
> > ret = qemu_file_get_error(f);
> > }
> >
> > - qemu_file_bin_input_visitor_cleanup(qfbiv);
> > + visit_destroy(v, &local_err);
> > return ret;
> > }
> >
> > --
> > 1.9.0
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK