Hey, This patchset is dependent on http://lists.xen.org/archives/html/xen-devel/2015-06/msg04812.html (Cleanups + various fixes due to libxl ABI + more logging on errors.).
During the discussion of http://lists.xen.org/archives/html/xen-devel/2015-06/msg01504.html "[PATCH QEMU-XEN] xen/pt: Start with emulated PCI_COMMAND set to zero." we got in a discussion about the xen/pt code usage of XenPTRreg->data and dev.config. The crux of the matter was that the PCI_COMMAND register read from the host changed from 0 to 3 (so PCI_COMMAND_IO and PCI_COMMAND_MEM were enabled). That messed up QEMU badly (thought it did recover) with some nasty messages on the Xen's ring buffer. Fast-forward and we came to the conclusion that: 1) The dev.config is (by Xen code) is used as the cache of the host configuration devices (which is OK at init right now). However to sync up the ->data with dev.config (and apply emu_mask) means that it cannot be used as such (the semantics of that have changed). We want dev.confg and ->data be synced up so that the initial guest values are not polluted with host register values which we are emulating. 2). The dev.config is (by the generic code) used as a view of what the guest should see (cache of guest values). This patchset moves in the direction of ripping out XenPTRreg->data and just using dev.config. Any time we want to consult the host values we will do so. These patches lay the groundwork and untangle some of the assumptions that the Xen code had made. The end goal (another patchset after this) will be that the XenPTRreg->data will vanish and will use dev.config as the sole source of guest cache values. Note: Only the first three patches are neccessary in the march toward this goal: [PATCH RFC 1 1/8] xen/pt: Use xen_host_pci_get_[byte|word] instead of [PATCH RFC 1 2/8] xen/pt: Sync up the dev.config and data values. [PATCH RFC 1 3/8] xen/pt: Check if reg->init is past the reg->size The rest are to piggyback on this and add proper error logging and reporting such that any bug fallout that comes out of this will be easier to tackle. I can move them way out to the end of the next patch series - but it might be easier to have them in this to help with bisection. Please review. hw/xen/xen-host-pci-device.c | 5 ++ hw/xen/xen-host-pci-device.h | 1 + hw/xen/xen_pt.c | 157 +++++++++++++++++++++++++++---------------- hw/xen/xen_pt.h | 2 + hw/xen/xen_pt_config_init.c | 135 ++++++++++++++++++++++++++++++------- hw/xen/xen_pt_msi.c | 18 +++-- 6 files changed, 231 insertions(+), 87 deletions(-) Konrad Rzeszutek Wilk (8): xen/pt: Use xen_host_pci_get_[byte|word] instead of dev.config xen/pt: Sync up the dev.config and data values. xen/pt: Check if reg->init is past the reg->size xen/pt: Log xen_host_pci_get in two init functions xen/pt: Log xen_host_pci_get/set errors in MSI code. xen/pt: Make xen_pt_unregister_device idempotent xen/pt: Move bulk of xen_pt_unregister_device in its own routine. xen/pt: Check for return values for xen_host_pci_[get|set] in init _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
