doc.patch

--- grub.texi	2019-03-07 23:16:41.936942741 +0100
+++ grub.texi	2019-03-07 23:36:24.682714121 +0100
@@ -3931,6 +3931,7 @@
 * play::                        Play a tune
 * probe::                       Retrieve device info
 * pxe_unload::                  Unload the PXE environment
+* rdmsr::                       Read values from model-specific registers
 * read::                        Read user input
 * reboot::                      Reboot your computer
 * regexp::                      Test if regular expression matches string
@@ -3953,6 +3954,7 @@
 * verify_detached::             Verify detached digital signature
 * videoinfo::                   List available video modes
 @comment * xen_*::              Xen boot commands for AArch64
+* wrmsr::                       Write values to model-specific registers
 * xen_hypervisor::              Load xen hypervisor binary (only on AArch64)
 * xen_module::                  Load xen modules for xen hypervisor (only on AArch64)
 @end menu
@@ -4785,6 +4787,24 @@
 @end deffn
 
 
+@node rdmsr
+@subsection rdmsr
+
+@deffn Command: rdmsr 0xADDR [-v VARNAME]
+Read a model-specific register at address 0xADDR. If the parameter
+@option{-v} is used and an environment variable @var{VARNAME} is 
+given, set that environment variable to the value that was read.
+
+Please note that on SMP systems, reading from a MSR that has a
+scope per hardware thread, implies that the value that is returned
+only applies to the particular cpu/core/thread that runs the command.
+
+Also, if you specify a reserved or unimplemented MSR address, it will 
+cause a general protection exception (which is not currently being handled)
+and the system will reboot.
+@end deffn
+
+
 @node read
 @subsection read
 
@@ -5223,6 +5243,21 @@
 List available video modes. If resolution is given, show only matching modes.
 @end deffn
 
+@node wrmsr
+@subsection wrmsr
+
+@deffn Command: wrmsr 0xADDR 0xVALUE
+Write a 0xVALUE to a model-specific register at address 0xADDR.
+
+Please note that on SMP systems, writing to a MSR that has a scope 
+per hardware thread, implies that the value that is written
+only applies to the particular cpu/core/thread that runs the command.
+
+Also, if you specify a reserved or unimplemented MSR address, it will 
+cause a general protection exception (which is not currently being handled)
+and the system will reboot.
+@end deffn
+
 @node xen_hypervisor
 @subsection xen_hypervisor
 
@@ -5716,11 +5751,11 @@
 is recommend to build in this and other required modules into the @file{core.img}.
 All modules not stored in the @file{core.img} and the ACPI tables for the
 @command{acpi} command have to be signed, e.g. using PGP. Additionally, the
-@command{iorw} and the @command{memrw} commands are prohibited if the UEFI
-secure boot is enabled. This is done due to security reasons. All above
-mentioned requirements are enforced by the shim_lock module. And itself it
-is a persistent module which means that it cannot be unloaded if it was
-loaded into the memory.
+@command{iorw}, the @command{memrw} and the @command{wrmsr} commands are 
+prohibited if the UEFI secure boot is enabled.  This is done due to 
+security reasons.  All above mentioned requirements are enforced by the 
+shim_lock module. And itself it is a persistent module which means that 
+it cannot be unloaded if it was loaded into the memory.
 
 @node Measured Boot
 @section Measuring boot components
@@ -5831,6 +5866,8 @@
 @item USB                @tab yes     @tab yes      @tab yes          @tab yes
 @item chainloader        @tab local   @tab yes      @tab yes          @tab no
 @item cpuid              @tab partial @tab partial  @tab partial      @tab partial
+@item rdmsr              @tab partial @tab partial  @tab partial      @tab partial
+@item wrmsr              @tab partial @tab partial  @tab partial      @tab partial
 @item hints              @tab guess   @tab guess    @tab guess        @tab guess
 @item PCI                @tab yes     @tab yes      @tab yes          @tab yes
 @item badram             @tab yes     @tab yes      @tab yes          @tab yes
@@ -5850,6 +5887,8 @@
 @item USB                @tab yes         @tab yes       @tab yes           @tab no
 @item chainloader        @tab local       @tab local     @tab no            @tab local
 @item cpuid              @tab partial     @tab partial   @tab partial       @tab no
+@item rdmsr              @tab partial     @tab partial   @tab partial       @tab no
+@item wrmsr              @tab partial     @tab partial   @tab partial       @tab no
 @item hints              @tab guess       @tab guess     @tab good          @tab guess
 @item PCI                @tab yes         @tab yes       @tab yes           @tab no
 @item badram             @tab yes         @tab yes       @tab no            @tab yes
@@ -5869,6 +5908,8 @@
 @item USB                @tab yes         @tab no      @tab no      @tab no
 @item chainloader        @tab yes         @tab no      @tab no      @tab no
 @item cpuid              @tab no          @tab no      @tab no      @tab no
+@item rdmsr              @tab no          @tab no      @tab no      @tab no
+@item wrmsr              @tab no          @tab no      @tab no      @tab no
 @item hints              @tab good        @tab good    @tab good    @tab no
 @item PCI                @tab yes         @tab no      @tab no      @tab no
 @item badram             @tab yes (*)     @tab no      @tab no      @tab no
@@ -5888,6 +5929,8 @@
 @item USB                @tab N/A       @tab yes         @tab no
 @item chainloader        @tab yes       @tab no          @tab yes
 @item cpuid              @tab no        @tab no          @tab yes
+@item rdmsr              @tab no        @tab no          @tab yes
+@item wrmsr              @tab no        @tab no          @tab yes
 @item hints              @tab guess     @tab no          @tab no
 @item PCI                @tab no        @tab no          @tab no
 @item badram             @tab yes (*)   @tab no          @tab no