Add support for ignoring disks devices on specific host controllers to
libata. Use this support to trigger us to ignore Hyper-V disk devices
on the emulated SATA device based on the system DMI information.
Fixes based on feedback Sergei Shtylyov, thanks. Jeff I think this is
about done, any objections to merging?
Comments?
-apw
V5
- switched to IS_ENABLED
- fixed device type in device ignored messages
V4
- only enable the quirk when the paravirtualised drivers are compiled
- fix up the command line flag to disable this support
V3
- switch detection method to DMI information
V2
- create a generic libata quirk
- switch detection to piix_init_one
Andy Whitcroft (2):
libata: add a host flag to ignore detected ATA devices
ata_piix: defer disks to the Hyper-V drivers by default
drivers/ata/ata_piix.c | 20 ++++++++++++++++++++
drivers/ata/libata-core.c | 7 +++++++
include/linux/libata.h | 1 +
3 files changed, 28 insertions(+)
--
1.7.9.5
Andy Whitcroft (2):
libata: add a host flag to ignore detected ATA devices
ata_piix: defer disks to the Hyper-V drivers by default
drivers/ata/ata_piix.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/ata/libata-core.c | 6 ++++++
include/linux/libata.h | 1 +
3 files changed, 43 insertions(+)
--
1.7.9.5
Where devices are visible via more than one host we sometimes wish to
indicate that cirtain devices should be ignored on a specific host. Add a
host flag indicating that this host wishes to ignore ATA specific devices.
Signed-off-by: Andy Whitcroft <[email protected]>
---
drivers/ata/libata-core.c | 6 ++++++
include/linux/libata.h | 1 +
2 files changed, 7 insertions(+)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e0bda9f..18e87bf 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1973,6 +1973,12 @@ retry:
if (class == ATA_DEV_ATA) {
if (!ata_id_is_ata(id) && !ata_id_is_cfa(id))
goto err_out;
+ if (ap->host->flags & ATA_HOST_IGNORE_ATA &&
+ ata_id_is_ata(id)) {
+ ata_dev_dbg(dev,
+ "host indicates ignore ATA devices, ignored\n");
+ return -ENOENT;
+ }
} else {
if (ata_id_is_ata(id))
goto err_out;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 42378d6..198c8f1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -247,6 +247,7 @@ enum {
ATA_HOST_SIMPLEX = (1 << 0), /* Host is simplex, one DMA channel per host only */
ATA_HOST_STARTED = (1 << 1), /* Host started */
ATA_HOST_PARALLEL_SCAN = (1 << 2), /* Ports on this host can be scanned in parallel */
+ ATA_HOST_IGNORE_ATA = (1 << 3), /* Ignore ATA devices on this host. */
/* bits 24:31 of host->flags are reserved for LLD specific flags */
--
1.7.9.5
When we are hosted on a Microsoft Hyper-V hypervisor the guest disks
are exposed both via the Hyper-V paravirtualised drivers and via an
emulated SATA disk drive. In this case we want to use the paravirtualised
drivers if we can as they are much more efficient. Note that the Hyper-V
paravirtualised drivers only expose the virtual hard disk devices, the
CDROM/DVD devices must still be enumerated.
Mark the host controller ATA_HOST_IGNORE_ATA to prevent enumeration of
disk devices.
BugLink: http://bugs.launchpad.net/bugs/929545
BugLink: http://bugs.launchpad.net/bugs/942316
Signed-off-by: Andy Whitcroft <[email protected]>
---
drivers/ata/ata_piix.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 68013f9..8fea06b 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -1552,6 +1552,39 @@ static bool piix_broken_system_poweroff(struct pci_dev *pdev)
return false;
}
+static int prefer_ms_hyperv = 1;
+module_param(prefer_ms_hyperv, int, 0);
+
+static void piix_ignore_devices_quirk(struct ata_host *host)
+{
+#if IS_ENABLED(CONFIG_HYPERV_STORAGE)
+ static const struct dmi_system_id ignore_hyperv[] = {
+ {
+ /* On Hyper-V hypervisors the disks are exposed on
+ * both the emulated SATA controller and on the
+ * paravirtualised drivers. The CD/DVD devices
+ * are only exposed on the emulated controller.
+ * Request we ignore ATA devices on this host.
+ */
+ .ident = "Hyper-V Virtual Machine",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR,
+ "Microsoft Corporation"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),
+ },
+ },
+ { } /* terminate list */
+ };
+ const struct dmi_system_id *dmi = dmi_first_match(ignore_hyperv);
+
+ if (dmi && prefer_ms_hyperv) {
+ host->flags |= ATA_HOST_IGNORE_ATA;
+ dev_info(host->dev, "%s detected, ATA device ignore set\n",
+ dmi->ident);
+ }
+#endif
+}
+
/**
* piix_init_one - Register PIIX ATA PCI device with kernel services
* @pdev: PCI device to register
@@ -1667,6 +1700,9 @@ static int __devinit piix_init_one(struct pci_dev *pdev,
}
host->flags |= ATA_HOST_PARALLEL_SCAN;
+ /* Allow hosts to specify device types to ignore when scanning. */
+ piix_ignore_devices_quirk(host);
+
pci_set_master(pdev);
return ata_pci_sff_activate_host(host, ata_bmdma_interrupt, sht);
}
--
1.7.9.5
On 05/04/2012 05:15 PM, Andy Whitcroft wrote:
> Where devices are visible via more than one host we sometimes wish to
> indicate that cirtain devices should be ignored on a specific host. Add a
> host flag indicating that this host wishes to ignore ATA specific devices.
>
> Signed-off-by: Andy Whitcroft<[email protected]>
applied 1-2