[PATCH 6/7] video/vesa: drop "vesa-mtrr" command line option

[Jan Beulich <jbeulich@xxxxxxxx>]

Now that we use ioremap_wc() for mapping the frame buffer, there's no
need for this option anymore. As noted in the change introducing the
use of ioremap_wc(), mtrr_add() didn't work in certain cases anyway.

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

--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog
 
 ## [unstable 
UNRELEASED](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=staging) - 
TBD
 
+### Removed / support downgraded
+ - dropped support for the (x86-only) "vesa-mtrr" command line option
+
 ## [4.15.0 
UNRELEASED](https://xenbits.xen.org/gitweb/?p=xen.git;a=shortlog;h=RELEASE-4.15.0)
 - TBD
 
 ### Added / support upgraded
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -2369,9 +2369,6 @@ cache-warming. 1ms (1000) has been measu
 ### vesa-map
 > `= <integer>`
 
-### vesa-mtrr
-> `= <integer>`
-
 ### vesa-ram
 > `= <integer>`
 
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1813,8 +1813,6 @@ void __init noreturn __start_xen(unsigne
 
     local_irq_enable();
 
-    vesa_mtrr_init();
-
     early_msi_init();
 
     iommu_setup();    /* setup iommu if available */
--- a/xen/drivers/video/vesa.c
+++ b/xen/drivers/video/vesa.c
@@ -145,38 +145,6 @@ void __init vesa_init(void)
     video_puts = lfb_redraw_puts;
 }
 
-#include <asm/mtrr.h>
-
-static unsigned int vesa_mtrr;
-integer_param("vesa-mtrr", vesa_mtrr);
-
-void __init vesa_mtrr_init(void)
-{
-    static const int mtrr_types[] = {
-        0, MTRR_TYPE_UNCACHABLE, MTRR_TYPE_WRBACK,
-        MTRR_TYPE_WRCOMB, MTRR_TYPE_WRTHROUGH };
-    unsigned int size_total;
-    int rc, type;
-
-    if ( !lfb || (vesa_mtrr == 0) || (vesa_mtrr >= ARRAY_SIZE(mtrr_types)) )
-        return;
-
-    type = mtrr_types[vesa_mtrr];
-    if ( !type )
-        return;
-
-    /* Find the largest power-of-two */
-    size_total = vram_total;
-    while ( size_total & (size_total - 1) )
-        size_total &= size_total - 1;
-
-    /* Try and find a power of two to add */
-    do {
-        rc = mtrr_add(lfb_base(), size_total, type, 1);
-        size_total >>= 1;
-    } while ( (size_total >= PAGE_SIZE) && (rc == -EINVAL) );
-}
-
 static void lfb_flush(void)
 {
     __asm__ __volatile__ ("sfence" : : : "memory");
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -25,10 +25,8 @@ void init_IRQ(void);
 
 #ifdef CONFIG_VIDEO
 void vesa_init(void);
-void vesa_mtrr_init(void);
 #else
 static inline void vesa_init(void) {};
-static inline void vesa_mtrr_init(void) {};
 #endif
 
 int construct_dom0(