To disable serial port for ia64 dom0 (RE: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64)
Serial can be disabled by a simple change: diff -r 2e5d4e459c1c buildconfigs/linux-defconfig_xen_ia64 --- a/buildconfigs/linux-defconfig_xen_ia64 Sun May 21 07:31:02 2006 -0600 +++ b/buildconfigs/linux-defconfig_xen_ia64 Mon May 22 15:06:00 2006 +0800 @@ -98,6 +98,7 @@ CONFIG_XEN_BLKDEV_FRONTEND=y CONFIG_XEN_BLKDEV_FRONTEND=y CONFIG_XEN_BACKEND=y CONFIG_XEN_BLKDEV_BACKEND=y +CONFIG_XEN_DISABLE_SERIAL=y CONFIG_XEN_SYSFS=y CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y CONFIG_DMA_IS_DMA32=y @@ -1544,4 +1545,3 @@ CONFIG_CRYPTO_DES=y # XEN # # CONFIG_XEN_UNPRIVILEGED_GUEST is not set -# CONFIG_XEN_DISABLE_SERIAL is not set But I'm not sure why I have to set option to be 'yes' explicitly: config XEN_DISABLE_SERIAL bool Disable serial port drivers default y So after making oldconfig, this option should be enabled automatically. Does I misunderstand the logic behind? :-( Thanks, Kevin -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tian, Kevin Sent: 2006年5月22日 14:53 To: Isaku Yamahata Cc: xen-ia64-devel@lists.xensource.com Subject: RE: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64 From: Isaku Yamahata [mailto:[EMAIL PROTECTED] Sent: 2006年5月22日 13:43 On Mon, May 22, 2006 at 12:53:11PM +0800, Tian, Kevin wrote: Why is serial required to be disabled in dom0? What's policy to choose which serial to be disabled, if there're multiple serial ports with different type? In fact I'm not sure about the policy. Since xenLinux/x86 defines CONFIG_XEN_DISABLE_SERIAL=y, I thought it was the xen's policy. However I'm not sure whether it's right. It seemed that you used serial port from dom0, I wanted to confirm it. It is bad that xen and dom0 accesse to the same UART. This is only what I'm sure about. Yes, that's bad which may be the reason why xen/x86 disables serial directly. Ideally that should also apply to xen/ia64 since that option is common in drivers/xen. So I'm not sure why that option doesn't work for ia64. Alex should know more about this area, and it may simply come from a mis-configuration case... Thanks, Kevin ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
RE: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64
On Mon, 2006-05-22 at 14:53 +0800, Tian, Kevin wrote: From: Isaku Yamahata [mailto:[EMAIL PROTECTED] It is bad that xen and dom0 accesse to the same UART. This is only what I'm sure about. Yes, that's bad which may be the reason why xen/x86 disables serial directly. Ideally that should also apply to xen/ia64 since that option is common in drivers/xen. So I'm not sure why that option doesn't work for ia64. Alex should know more about this area, and it may simply come from a mis-configuration case... Configuring the serial console is far more painful than it should be right now on xen/ia64. This is due to the fact that xen and xenlinux both claim the same physical UART. On xen/x86, the physical UARTs are hidden from xenlinux using the config option such that only xen talks to the physical hardware and ttyS0 on xenlinux is actually xencons. Xen/ia64 leaves the serial driver in place, which allows xenlinux to claim the physical UART. We therefore have to disable input in xencons and play games with assigning xencons to ttyS values outside of what the serial driver typically claims. While not ideal, I think we should take the xen/x86 approach and disable serial access from dom0. At some point maybe we can add support to hide only the physical UART used by xen and allow dom0 to access any others that might be available. Such a feature would need to be aware of both I/O port and MMIO UARTs and handle UARTs described in ACPI namespace. Thanks, Alex -- Alex Williamson HP Linux Open Source Lab ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
Re: To disable serial port for ia64 dom0 (RE: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64)
On Mon, 2006-05-22 at 15:22 +0800, Tian, Kevin wrote: But I'm not sure why I have to set option to be 'yes' explicitly: config XEN_DISABLE_SERIAL bool Disable serial port drivers default y So after making oldconfig, this option should be enabled automatically. Does I misunderstand the logic behind? :-( The is not set is logically equivalent to =n, so it's disabled because of our default config in buildconfigs. Thanks, Alex -- Alex Williamson HP Linux Open Source Lab ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
Re: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64
On Mon, 2006-05-22 at 16:26 +0200, Tristan Gingold wrote: Le Lundi 22 Mai 2006 16:12, Alex Williamson a écrit : Such a feature would need to be aware of both I/O port and MMIO UARTs and handle UARTs described in ACPI namespace. Thanks, Modifying ACPI to hide an UART seems to be very hard... Yes, very hard might even be an understatement ;^) Just an idea: if UART is used by Xen, it should reverse the interrupt line (unless shared...) In this case, Linux shouldn't be allowed to register an handler for this IRQ and should fail to use the UART. Right ? Good thought, I'd have to look at the serial driver to see what it would do in that case. It might end up switching to polling mode and still try to use the UART. Thanks, Alex -- Alex Williamson HP Linux Open Source Lab ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
RE: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64
While not ideal, I think we should take the xen/x86 approach and disable serial access from dom0. At some point maybe we can add support to hide only the physical UART used by xen and allow dom0 to access any others that might be available. Such a feature would need to be aware of both I/O port and MMIO UARTs and handle UARTs described in ACPI namespace. Thanks, Please try to turn off the dom0 console dynamically rather than via config option. It would be a shame to lose transparent paravirtualization just to turn off the console. ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
Re: [Xen-ia64-devel] [PATCH 0/6] Add full evtchn mechanism forxen/ia64
On Mon, May 22, 2006 at 12:53:11PM +0800, Tian, Kevin wrote: Why is serial required to be disabled in dom0? What's policy to choose which serial to be disabled, if there're multiple serial ports with different type? In fact I'm not sure about the policy. Since xenLinux/x86 defines CONFIG_XEN_DISABLE_SERIAL=y, I thought it was the xen's policy. However I'm not sure whether it's right. It seemed that you used serial port from dom0, I wanted to confirm it. It is bad that xen and dom0 accesse to the same UART. This is only what I'm sure about. -- yamahata ___ Xen-ia64-devel mailing list Xen-ia64-devel@lists.xensource.com http://lists.xensource.com/xen-ia64-devel
