From: Julien Grall Date: Fri, 1 Mar 2019 15:39:21 +0000 (+0000) Subject: xen/public: Document HYPERCALL_console_io() X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~1735 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=61f82e8dfd1a37b432ee227caaae354c2abe02b5;p=xen.git xen/public: Document HYPERCALL_console_io() Currently, OS developpers will have to look at Xen code in order to know the parameters of an hypercall and how it is meant to work. This is not a trivial task as you may need to have a deep understanding of Xen internal. This patch attempts to document the behavior of HYPERCALL_console_io() to help OS developer. Signed-off-by: Julien Grall Acked-by: Jan Beulich --- diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h index cb2917e74b..0c7b5c3865 100644 --- a/xen/include/public/xen.h +++ b/xen/include/public/xen.h @@ -486,7 +486,28 @@ DEFINE_XEN_GUEST_HANDLE(mmuext_op_t); /* ` } */ /* - * Commands to HYPERVISOR_console_io(). + * ` int + * ` HYPERVISOR_console_io(unsigned int cmd, + * ` unsigned int count, + * ` char buffer[]); + * + * @cmd: Command (see below) + * @count: Size of the buffer to read/write + * @buffer: Pointer in the guest memory + * + * List of commands: + * + * * CONSOLEIO_write: Write the buffer to Xen console. + * For the hardware domain, all the characters in the buffer will + * be written. Characters will be printed directly to the console. + * For all the other domains, only the printable characters will be + * written. Characters may be buffered until a newline (i.e '\n') is + * found. + * @return 0 on success, otherwise return an error code. + * * CONSOLEIO_read: Attempts to read up to @count characters from Xen + * console. The maximum buffer size (i.e. @count) supported is 2GB. + * @return the number of characters read on success, otherwise return + * an error code. */ #define CONSOLEIO_write 0 #define CONSOLEIO_read 1