Commit f1613a9e authored by Committed by Greg Kroah-HartmanBrowse files
xen/pciback: Don't disable PCI_COMMAND on PCI device reset.
commit 7681f31ec9cdacab4fd10570be924f2cef6669ba upstream. There is no need for this at all. Worst it means that if the guest tries to write to BARs it could lead (on certain platforms) to PCI SERR errors. Please note that with af6fc858 "xen-pciback: limit guest control of command register" a guest is still allowed to enable those control bits (safely), but is not allowed to disable them and that therefore a well behaved frontend which enables things before using them will still function correctly. This is done via an write to the configuration register 0x4 which triggers on the backend side: command_write \- pci_enable_device \- pci_enable_device_flags \- do_pci_enable_device \- pcibios_enable_device \-pci_enable_resourcess [which enables the PCI_COMMAND_MEMORY|PCI_COMMAND_IO] However guests (and drivers) which don't do this could cause problems, including the security issues which XSA-120 sought to address. Reported-by: Jan Beulich <email@example.com> Signed-off-by: Konrad Rzeszutek Wilk <firstname.lastname@example.org> Reviewed-by: Prarit Bhargava <email@example.com> Signed-off-by: Juergen Gross <firstname.lastname@example.org> Cc: Ben Hutchings <email@example.com> Signed-off-by: Greg Kroah-Hartman <firstname.lastname@example.org>