[Xen-changelog] [xen stable-4.4] EFI: support default attributes to map Runtime service areas with none given

[patchbot@xxxxxxx]

commit d108622ce5874ced4c3951d4c94a886e302e30e1
Author:     Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
AuthorDate: Thu Jun 18 09:38:37 2015 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jun 18 09:38:37 2015 +0200

    EFI: support default attributes to map Runtime service areas with none given
    
    From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    
    For example on Dell machines we see:
    
    (XEN)  00000fed18000-00000fed19fff type=11 attr=8000000000000000
    (XEN) Unknown cachability for MFNs 0xfed18-0xfed19
    
    Let's allow them to be mapped as UC.
    
    We also alter the 'efi-rs' to be 'efi=rs' or 'efi=no-rs'.
    
    Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    master commit: 74cdad5dae72c78af4f6b343f38fd55e6a526ab1
    master date: 2015-06-10 12:04:07 +0200
---
 docs/misc/xen-command-line.markdown |   18 +++++++++++++++---
 xen/arch/x86/efi/boot.c             |   34 ++++++++++++++++++++++++++++++----
 2 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown 
b/docs/misc/xen-command-line.markdown
index 304588e..77790af 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -497,12 +497,24 @@ Either force retrieval of monitor EDID information via 
VESA DDC, or
 disable it (edid=no). This option should not normally be required
 except for debugging purposes.
 
-### efi-rs
-> `= <boolean>`
+### efi
+> `= List of [ rs | attr ]`
+
+All options are of boolean kind and can be prefixed with `no-` to
+effect the inverse meaning.
+
+> `rs`
 
 > Default: `true`
 
-Force or disable use of EFI runtime services.
+>> Force or disable use of EFI runtime services.
+
+> `attr=uc`
+
+> Default: `off`
+
+>> Allows mapping of RuntimeServices which have no cachability attribute
+>> set as UC.
 
 ### extra\_guest\_irqs
 > `= [<domU number>][,<dom0 number>]`
diff --git a/xen/arch/x86/efi/boot.c b/xen/arch/x86/efi/boot.c
index 7c50e80..8178aea 100644
--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -1530,7 +1530,31 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE 
*SystemTable)
 
 
 static bool_t __initdata efi_rs_enable = 1;
-boolean_param("efi-rs", efi_rs_enable);
+static bool_t __initdata efi_map_uc;
+
+static void __init parse_efi_param(char *s)
+{
+    char *ss;
+
+    do {
+        bool_t val = !!strncmp(s, "no-", 3);
+
+        if ( !val )
+            s += 3;
+
+        ss = strchr(s, ',');
+        if ( ss )
+            *ss = '\0';
+
+        if ( !strcmp(s, "rs") )
+            efi_rs_enable = val;
+        else if ( !strcmp(s, "attr=uc") )
+            efi_map_uc = val;
+
+        s = ss + 1;
+    } while ( ss );
+}
+custom_param("efi", parse_efi_param);
 
 #ifndef USE_SET_VIRTUAL_ADDRESS_MAP
 static __init void copy_mapping(unsigned long mfn, unsigned long end,
@@ -1628,9 +1652,11 @@ void __init efi_init_memory(void)
             prot |= _PAGE_PWT | _PAGE_PCD | MAP_SMALL_PAGES;
         else
         {
-            printk(XENLOG_ERR "Unknown cachability for MFNs %#lx-%#lx\n",
-                   smfn, emfn - 1);
-            continue;
+            printk(XENLOG_ERR "Unknown cachability for MFNs %#lx-%#lx%s\n",
+                   smfn, emfn - 1, efi_map_uc ? ", assuming UC" : "");
+            if ( !efi_map_uc )
+                continue;
+            prot |= _PAGE_PWT | _PAGE_PCD | MAP_SMALL_PAGES;
         }
 
         if ( desc->Attribute & EFI_MEMORY_WP )
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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