| Message ID | 1404480720-7485-5-git-send-email-armbru@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 04.07.2014 um 15:32 hat Markus Armbruster geschrieben: > The block layer fails such reads and writes just fine. However, they > then get treated like valid operations that fail: the error action > gets executed. Unwanted; reporting the error to the guest is the only > sensible action. > > Reject them before passing them to the block layer. This bypasses the > error action and, for PIO but not DMA, I/O accounting. Tolerable, > because I/O accounting is an inconsistent mess anyway. > > Signed-off-by: Markus Armbruster <armbru@redhat.com> > --- > hw/ide/core.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/hw/ide/core.c b/hw/ide/core.c > index 3a38f1e..63a500d 100644 > --- a/hw/ide/core.c > +++ b/hw/ide/core.c > @@ -499,6 +499,18 @@ static void ide_rw_error(IDEState *s) { > ide_set_irq(s->bus); > } > > +static bool ide_sect_range_ok(IDEState *s, > + uint64_t sector, uint64_t nb_sectors) > +{ > + uint64_t total_sectors; > + > + bdrv_get_geometry(s->bs, &total_sectors); > + if (sector > total_sectors || nb_sectors > total_sectors - sector) { > + return false; > + } > + return true; > +} > + > static void ide_sector_read_cb(void *opaque, int ret) > { > IDEState *s = opaque; > @@ -554,6 +566,11 @@ void ide_sector_read(IDEState *s) > printf("sector=%" PRId64 "\n", sector_num); > #endif > > + if (!ide_sect_range_ok(s, sector_num, n)) { > + ide_rw_error(s); > + return; > + } > + > s->iov.iov_base = s->io_buffer; > s->iov.iov_len = n * BDRV_SECTOR_SIZE; > qemu_iovec_init_external(&s->qiov, &s->iov, 1); > @@ -671,6 +688,12 @@ void ide_dma_cb(void *opaque, int ret) > sector_num, n, s->dma_cmd); > #endif > > + if (!ide_sect_range_ok(s, sector_num, n)) { > + dma_buf_commit(s); > + ide_dma_error(s); > + goto eot; Are you sure that this should be 'goto eot' rather than just 'return'? When jumping to eot, we do the I/O accounting (which we said we don't care about) and call ide_set_inactive() for a second time. The condition for setting BM_STATUS_DMAING is never met when coming from here. I am worried about ide_set_inactive() doing double request cleanup. Kevin
Kevin Wolf <kwolf@redhat.com> writes: > Am 04.07.2014 um 15:32 hat Markus Armbruster geschrieben: >> The block layer fails such reads and writes just fine. However, they >> then get treated like valid operations that fail: the error action >> gets executed. Unwanted; reporting the error to the guest is the only >> sensible action. >> >> Reject them before passing them to the block layer. This bypasses the >> error action and, for PIO but not DMA, I/O accounting. Tolerable, >> because I/O accounting is an inconsistent mess anyway. >> >> Signed-off-by: Markus Armbruster <armbru@redhat.com> >> --- >> hw/ide/core.c | 28 ++++++++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/hw/ide/core.c b/hw/ide/core.c >> index 3a38f1e..63a500d 100644 >> --- a/hw/ide/core.c >> +++ b/hw/ide/core.c >> @@ -499,6 +499,18 @@ static void ide_rw_error(IDEState *s) { >> ide_set_irq(s->bus); >> } >> >> +static bool ide_sect_range_ok(IDEState *s, >> + uint64_t sector, uint64_t nb_sectors) >> +{ >> + uint64_t total_sectors; >> + >> + bdrv_get_geometry(s->bs, &total_sectors); >> + if (sector > total_sectors || nb_sectors > total_sectors - sector) { >> + return false; >> + } >> + return true; >> +} >> + >> static void ide_sector_read_cb(void *opaque, int ret) >> { >> IDEState *s = opaque; >> @@ -554,6 +566,11 @@ void ide_sector_read(IDEState *s) >> printf("sector=%" PRId64 "\n", sector_num); >> #endif >> >> + if (!ide_sect_range_ok(s, sector_num, n)) { >> + ide_rw_error(s); >> + return; >> + } >> + >> s->iov.iov_base = s->io_buffer; >> s->iov.iov_len = n * BDRV_SECTOR_SIZE; >> qemu_iovec_init_external(&s->qiov, &s->iov, 1); >> @@ -671,6 +688,12 @@ void ide_dma_cb(void *opaque, int ret) >> sector_num, n, s->dma_cmd); >> #endif >> >> + if (!ide_sect_range_ok(s, sector_num, n)) { >> + dma_buf_commit(s); >> + ide_dma_error(s); >> + goto eot; > > Are you sure that this should be 'goto eot' rather than just 'return'? > When jumping to eot, we do the I/O accounting (which we said we don't > care about) and call ide_set_inactive() for a second time. The condition > for setting BM_STATUS_DMAING is never met when coming from here. > > I am worried about ide_set_inactive() doing double request cleanup. You're right; I missed the fact that ide_dma_error() calls ide_set_inactive() already. Immediate return also skips the other things happening after eot, but that's okay, because: * skipping the bdrv_acct_done() merely changes I/O accounting to be busted somewhat differently, and * stay_active is certainly false, so we don't actually skip anything there. Respin sent.
diff --git a/hw/ide/core.c b/hw/ide/core.c index 3a38f1e..63a500d 100644 --- a/hw/ide/core.c +++ b/hw/ide/core.c @@ -499,6 +499,18 @@ static void ide_rw_error(IDEState *s) { ide_set_irq(s->bus); } +static bool ide_sect_range_ok(IDEState *s, + uint64_t sector, uint64_t nb_sectors) +{ + uint64_t total_sectors; + + bdrv_get_geometry(s->bs, &total_sectors); + if (sector > total_sectors || nb_sectors > total_sectors - sector) { + return false; + } + return true; +} + static void ide_sector_read_cb(void *opaque, int ret) { IDEState *s = opaque; @@ -554,6 +566,11 @@ void ide_sector_read(IDEState *s) printf("sector=%" PRId64 "\n", sector_num); #endif + if (!ide_sect_range_ok(s, sector_num, n)) { + ide_rw_error(s); + return; + } + s->iov.iov_base = s->io_buffer; s->iov.iov_len = n * BDRV_SECTOR_SIZE; qemu_iovec_init_external(&s->qiov, &s->iov, 1); @@ -671,6 +688,12 @@ void ide_dma_cb(void *opaque, int ret) sector_num, n, s->dma_cmd); #endif + if (!ide_sect_range_ok(s, sector_num, n)) { + dma_buf_commit(s); + ide_dma_error(s); + goto eot; + } + switch (s->dma_cmd) { case IDE_DMA_READ: s->bus->dma->aiocb = dma_bdrv_read(s->bs, &s->sg, sector_num, @@ -790,6 +813,11 @@ void ide_sector_write(IDEState *s) n = s->req_nb_sectors; } + if (!ide_sect_range_ok(s, sector_num, n)) { + ide_rw_error(s); + return; + } + s->iov.iov_base = s->io_buffer; s->iov.iov_len = n * BDRV_SECTOR_SIZE; qemu_iovec_init_external(&s->qiov, &s->iov, 1);
The block layer fails such reads and writes just fine. However, they then get treated like valid operations that fail: the error action gets executed. Unwanted; reporting the error to the guest is the only sensible action. Reject them before passing them to the block layer. This bypasses the error action and, for PIO but not DMA, I/O accounting. Tolerable, because I/O accounting is an inconsistent mess anyway. Signed-off-by: Markus Armbruster <armbru@redhat.com> --- hw/ide/core.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)