[PATCH] x86/PVH: obtain VGA console info in Dom0

[Jan Beulich <jbeulich@xxxxxxxx>]

A new platform-op was added to Xen to allow obtaining the same VGA
console information PV Dom0 is handed. Invoke the new function and have
the output data processed by xen_init_vga().

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -45,6 +45,6 @@ obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinl
 
 obj-$(CONFIG_XEN_DEBUG_FS)     += debugfs.o
 
-obj-$(CONFIG_XEN_PV_DOM0)      += vga.o
+obj-$(CONFIG_XEN_DOM0)         += vga.o
 
 obj-$(CONFIG_XEN_EFI)          += efi.o
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1390,7 +1390,8 @@ asmlinkage __visible void __init xen_sta
 
                x86_platform.set_legacy_features =
                                xen_dom0_set_legacy_features;
-               xen_init_vga(info, xen_start_info->console.dom0.info_size);
+               xen_init_vga(info, xen_start_info->console.dom0.info_size,
+                            &boot_params.screen_info);
                xen_start_info->console.domU.mfn = 0;
                xen_start_info->console.domU.evtchn = 0;
 
--- a/arch/x86/xen/enlighten_pvh.c
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -43,6 +43,19 @@ void __init xen_pvh_init(struct boot_par
        x86_init.oem.banner = xen_banner;
 
        xen_efi_init(boot_params);
+
+       if (xen_initial_domain()) {
+               struct xen_platform_op op = {
+                       .cmd = XENPF_get_dom0_console,
+               };
+               long ret = HYPERVISOR_platform_op(&op);
+
+               if (ret > 0)
+                       xen_init_vga(&op.u.dom0_console,
+                                    min(ret * sizeof(char),
+                                        sizeof(op.u.dom0_console)),
+                                    &boot_params->screen_info);
+       }
 }
 
 void __init mem_map_via_hcall(struct boot_params *boot_params_p)
--- a/arch/x86/xen/vga.c
+++ b/arch/x86/xen/vga.c
@@ -9,10 +9,9 @@
 
 #include "xen-ops.h"
 
-void __init xen_init_vga(const struct dom0_vga_console_info *info, size_t size)
+void __init xen_init_vga(const struct dom0_vga_console_info *info, size_t size,
+                        struct screen_info *screen_info)
 {
-       struct screen_info *screen_info = &boot_params.screen_info;
-
        /* This is drawn from a dump from vgacon:startup in
         * standard Linux. */
        screen_info->orig_video_mode = 3;
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -108,11 +108,12 @@ static inline void xen_uninit_lock_cpu(i
 
 struct dom0_vga_console_info;
 
-#ifdef CONFIG_XEN_PV_DOM0
-void __init xen_init_vga(const struct dom0_vga_console_info *, size_t size);
+#ifdef CONFIG_XEN_DOM0
+void __init xen_init_vga(const struct dom0_vga_console_info *, size_t size,
+                        struct screen_info *);
 #else
 static inline void __init xen_init_vga(const struct dom0_vga_console_info 
*info,
-                                      size_t size)
+                                      size_t size, struct screen_info *si)
 {
 }
 #endif
--- a/include/xen/interface/platform.h
+++ b/include/xen/interface/platform.h
@@ -483,6 +483,8 @@ struct xenpf_symdata {
 };
 DEFINE_GUEST_HANDLE_STRUCT(xenpf_symdata);
 
+#define XENPF_get_dom0_console 64
+
 struct xen_platform_op {
        uint32_t cmd;
        uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
@@ -506,6 +508,7 @@ struct xen_platform_op {
                struct xenpf_mem_hotadd        mem_add;
                struct xenpf_core_parking      core_parking;
                struct xenpf_symdata           symdata;
+               struct dom0_vga_console_info   dom0_console;
                uint8_t                        pad[128];
        } u;
 };