emulators/xen-kernel: add fix for fetching video mode

Sponsored by: Citrix Systems R&D
Approved by: bapt (implicit)

emulators/xen-kernel/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	xen
 PORTVERSION=	4.17.0
-PORTREVISION=	0
+PORTREVISION=	1
 CATEGORIES=	emulators
 MASTER_SITES=	http://downloads.xenproject.org/release/xen/${PORTVERSION}/
 PKGNAMESUFFIX=	-kernel
@@ -34,7 +34,8 @@ EXTRA_PATCHES+=	${PATCHDIR}/xsa425.patch:-p1 \
 # clang build fixes
 EXTRA_PATCHES+=	${PATCHDIR}/0001-xen-x86-Remove-the-use-of-K-R-functions.patch:-p1
 # Support for fetching video mode from PVH dom0
-EXTRA_PATCHES+=	${PATCHDIR}/0001-x86-platform-introduce-hypercall-to-get-initial-vide.patch:-p1
+EXTRA_PATCHES+=	${PATCHDIR}/0001-x86-platform-introduce-hypercall-to-get-initial-vide.patch:-p1 \
+		${PATCHDIR}/0001-x86-platform-make-XENPF_get_dom0_console-actually-us.patch:-p1
 
 .include <bsd.port.options.mk>
 

emulators/xen-kernel/files/0001-x86-platform-make-XENPF_get_dom0_console-actually-us.patch

@@ -0,0 +1,58 @@
+From 7d43e4b2aa42b826e3d373b8e802ba925cc73088 Mon Sep 17 00:00:00 2001
+From: Jan Beulich <jbeulich@suse.com>
+Date: Mon, 13 Mar 2023 15:14:38 +0100
+Subject: [PATCH] x86/platform: make XENPF_get_dom0_console actually usable
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+struct dom0_vga_console_info has been extended in the past, and it may
+be extended again. The use in PV Dom0's start info already covers for
+that by supplying the size of the provided data. For the recently
+introduced platform-op size needs providing similarly. Go the easiest
+available route and simply supply size via the hypercall return value.
+
+While there also add a build-time check that possibly future growth of
+the struct won't affect xen_platform_op_t's size.
+
+Fixes: 4dd160583c79 ("x86/platform: introduce hypercall to get initial video console settings")
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+Acked-by: Roger Pau Monné <roger.pau@citrix.com>
+---
+ xen/arch/x86/platform_hypercall.c | 2 ++
+ xen/include/public/platform.h     | 6 +++++-
+ 2 files changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/xen/arch/x86/platform_hypercall.c b/xen/arch/x86/platform_hypercall.c
+index 08ab2fea62..85c69c5be5 100644
+--- a/xen/arch/x86/platform_hypercall.c
++++ b/xen/arch/x86/platform_hypercall.c
+@@ -841,6 +841,8 @@ ret_t do_platform_op(
+
+ #ifdef CONFIG_VIDEO
+     case XENPF_get_dom0_console:
++        BUILD_BUG_ON(sizeof(op->u.dom0_console) > sizeof(op->u.pad));
++        ret = sizeof(op->u.dom0_console);
+         if ( !fill_console_start_info(&op->u.dom0_console) )
+         {
+             ret = -ENODEV;
+diff --git a/xen/include/public/platform.h b/xen/include/public/platform.h
+index 14784dfa77..60caa5ce7e 100644
+--- a/xen/include/public/platform.h
++++ b/xen/include/public/platform.h
+@@ -605,7 +605,11 @@ struct xenpf_symdata {
+ typedef struct xenpf_symdata xenpf_symdata_t;
+ DEFINE_XEN_GUEST_HANDLE(xenpf_symdata_t);
+
+-/* Fetch the video console information and mode setup by Xen. */
++/*
++ * Fetch the video console information and mode setup by Xen.  A non-
++ * negative return value indicates the size of the (part of the) structure
++ * which was filled.
++ */
+ #define XENPF_get_dom0_console 64
+ typedef struct dom0_vga_console_info xenpf_dom0_console_t;
+ DEFINE_XEN_GUEST_HANDLE(xenpf_dom0_console_t);
+-- 
+2.39.0
+