Commit 090fa1c8 "add support for unplugging NVMe disks..." extended the existing disk unplug flag to cover NVMe disks as well as IDE and SCSI.
The recent thread on the xen-devel mailing list [1] has highlighted that this is not desirable behaviour: PV frontends should be able to distinguish NVMe disks from other types of disk and should have separate control over whether they are unplugged. This patch defines a new bit in the unplug mask for this purpose and also tidies up the definitions of, and improves the comments regarding, the previously exiting bits in the protocol. [1] https://lists.xen.org/archives/html/xen-devel/2017-03/msg02924.html Signed-off-by: Paul Durrant <paul.durr...@citrix.com> -- Cc: Stefano Stabellini <sstabell...@kernel.org> Cc: Anthony Perard <anthony.per...@citrix.com> NOTE: A companion patch will be submitted to xen-devel to align the unplug protocol documentation once this patch is acked. v2: - Fix the commit comment --- hw/i386/xen/xen_platform.c | 47 ++++++++++++++++++++++++++++++++++------------ 1 file changed, 35 insertions(+), 12 deletions(-) diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c index 6010f35..983d532 100644 --- a/hw/i386/xen/xen_platform.c +++ b/hw/i386/xen/xen_platform.c @@ -87,10 +87,30 @@ static void log_writeb(PCIXenPlatformState *s, char val) } } -/* Xen Platform, Fixed IOPort */ -#define UNPLUG_ALL_DISKS 1 -#define UNPLUG_ALL_NICS 2 -#define UNPLUG_AUX_IDE_DISKS 4 +/* + * Unplug device flags. + * + * The logic got a little confused at some point in the past but this is + * what they do now. + * + * bit 0: Unplug all IDE and SCSI disks. + * bit 1: Unplug all NICs. + * bit 2: Unplug IDE disks except primary master. This is overridden if + * bit 0 is also present in the mask. + * bit 3: Unplug all NVMe disks. + * + */ +#define _UNPLUG_IDE_SCSI_DISKS 0 +#define UNPLUG_IDE_SCSI_DISKS (1u << _UNPLUG_IDE_SCSI_DISKS) + +#define _UNPLUG_ALL_NICS 1 +#define UNPLUG_ALL_NICS (1u << _UNPLUG_ALL_NICS) + +#define _UNPLUG_AUX_IDE_DISKS 2 +#define UNPLUG_AUX_IDE_DISKS (1u << _UNPLUG_AUX_IDE_DISKS) + +#define _UNPLUG_NVME_DISKS 3 +#define UNPLUG_NVME_DISKS (1u << _UNPLUG_NVME_DISKS) static void unplug_nic(PCIBus *b, PCIDevice *d, void *o) { @@ -111,7 +131,7 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque) { uint32_t flags = *(uint32_t *)opaque; bool aux = (flags & UNPLUG_AUX_IDE_DISKS) && - !(flags & UNPLUG_ALL_DISKS); + !(flags & UNPLUG_IDE_SCSI_DISKS); /* We have to ignore passthrough devices */ if (!strcmp(d->name, "xen-pci-passthrough")) { @@ -124,12 +144,16 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque) break; case PCI_CLASS_STORAGE_SCSI: - case PCI_CLASS_STORAGE_EXPRESS: if (!aux) { object_unparent(OBJECT(d)); } break; + case PCI_CLASS_STORAGE_EXPRESS: + if (flags & UNPLUG_NVME_DISKS) { + object_unparent(OBJECT(d)); + } + default: break; } @@ -147,10 +171,9 @@ static void platform_fixed_ioport_writew(void *opaque, uint32_t addr, uint32_t v switch (addr) { case 0: { PCIDevice *pci_dev = PCI_DEVICE(s); - /* Unplug devices. Value is a bitmask of which devices to - unplug, with bit 0 the disk devices, bit 1 the network - devices, and bit 2 the non-primary-master IDE devices. */ - if (val & (UNPLUG_ALL_DISKS | UNPLUG_AUX_IDE_DISKS)) { + /* Unplug devices. See comment above flag definitions */ + if (val & (UNPLUG_IDE_SCSI_DISKS | UNPLUG_AUX_IDE_DISKS | + UNPLUG_NVME_DISKS)) { DPRINTF("unplug disks\n"); pci_unplug_disks(pci_dev->bus, val); } @@ -338,14 +361,14 @@ static void xen_platform_ioport_writeb(void *opaque, hwaddr addr, * If VMDP was to control both disk and LAN it would use 4. * If it controlled just disk or just LAN, it would use 8 below. */ - pci_unplug_disks(pci_dev->bus, UNPLUG_ALL_DISKS); + pci_unplug_disks(pci_dev->bus, UNPLUG_IDE_SCSI_DISKS); pci_unplug_nics(pci_dev->bus); } break; case 8: switch (val) { case 1: - pci_unplug_disks(pci_dev->bus, UNPLUG_ALL_DISKS); + pci_unplug_disks(pci_dev->bus, UNPLUG_IDE_SCSI_DISKS); break; case 2: pci_unplug_nics(pci_dev->bus); -- 2.1.4
