Re: [Xen-devel] [PATCH 2/2] CA-162192: Fix rebooting on some EFI-booted systems

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On March 12, 2015 7:44:58 AM EDT, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 11.03.15 at 19:49, <konrad.wilk@xxxxxxxxxx> wrote:
>> From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>> Date: Tue, 3 Feb 2015 11:18:04 -0500
>> Subject: [PATCH] efi: Allow reboot= overrides when running under EFI
>> 
>> By default we will always use EFI reboot mechanism when
>> running under EFI platforms. However some EFI platforms
>> are buggy and need to use the ACPI mechanism to
>> reboot (such as Lenovo ThinkCentre M57). As such
>> respect the 'reboot=' override and DMI overrides
>> for EFI platforms.
>> 
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>
>Further re-worked (hopefully we're reaching something
>everyone is okay with):
>
>efi: Allow reboot= overrides when running under EFI
>
>By default we will always use EFI reboot mechanism when
>running under EFI platforms. However some EFI platforms
>are buggy and need to use the ACPI mechanism to
>reboot (such as Lenovo ThinkCentre M57). As such
>respect the 'reboot=' override and DMI overrides
>for EFI platforms.
>
>Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

And Reviewed-by as well.
>
>- BOOT_INVALID is just zero
>- also consider acpi_disabled in BOOT_INVALID resolution
>- duplicate BOOT_INVALID resolution in machine_restart()
>- don't fall back from BOOT_ACPI to BOOT_EFI (if it was overridden, it
>  surely was for a reason)
>- adjust doc change formatting
>
>Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
>--- a/docs/misc/xen-command-line.markdown
>+++ b/docs/misc/xen-command-line.markdown
>@@ -1145,7 +1145,7 @@ The following resources are available:
>   Technology.
> 
> ### reboot
>-> `= t[riple] | k[bd] | a[cpi] | p[ci] | n[o] [, [w]arm | [c]old]`
>+> `= t[riple] | k[bd] | a[cpi] | p[ci] | e[fi] | n[o] [, [w]arm |
>[c]old]`
> 
> > Default: `0`
> 
>@@ -1165,6 +1165,9 @@ Specify the host reboot method.
> 
>`pci` instructs Xen to reboot the host using PCI reset register (port
>CF9).
> 
>+'efi' instructs Xen to reboot using the EFI reboot call (in EFI mode
>by
>+ default it will use that method first).
>+
> ### ro-hpet
> > `= <boolean>`
> 
>--- a/xen/arch/x86/shutdown.c
>+++ b/xen/arch/x86/shutdown.c
>@@ -28,16 +28,18 @@
> #include <asm/apic.h>
> 
> enum reboot_type {
>+        BOOT_INVALID,
>         BOOT_TRIPLE = 't',
>         BOOT_KBD = 'k',
>         BOOT_ACPI = 'a',
>         BOOT_CF9 = 'p',
>+        BOOT_EFI = 'e',
> };
> 
> static int reboot_mode;
> 
> /*
>- * reboot=t[riple] | k[bd] | a[cpi] | p[ci] | n[o] [, [w]arm | [c]old]
>+ * reboot=t[riple] | k[bd] | a[cpi] | p[ci] | n[o] | [e]fi [, [w]arm |
>[c]old]
>  * warm   Don't set the cold reboot flag
>  * cold   Set the cold reboot flag
>  * no     Suppress automatic reboot after panics or crashes
>@@ -45,8 +47,9 @@ static int reboot_mode;
>  * kbd    Use the keyboard controller. cold reset (default)
>  * acpi   Use the RESET_REG in the FADT
>  * pci    Use the so-called "PCI reset register", CF9
>+ * efi    Use the EFI reboot (if running under EFI)
>  */
>-static enum reboot_type reboot_type = BOOT_ACPI;
>+static enum reboot_type reboot_type = BOOT_INVALID;
> static void __init set_reboot_type(char *str)
> {
>     for ( ; ; )
>@@ -63,6 +66,7 @@ static void __init set_reboot_type(char 
>             reboot_mode = 0x0;
>             break;
>         case 'a':
>+        case 'e':
>         case 'k':
>         case 't':
>         case 'p':
>@@ -106,6 +110,14 @@ void machine_halt(void)
>     __machine_halt(NULL);
> }
> 
>+static void default_reboot_type(void)
>+{
>+    if ( reboot_type == BOOT_INVALID )
>+        reboot_type = efi_enabled ? BOOT_EFI
>+                                  : acpi_disabled ? BOOT_KBD
>+                                                  : BOOT_ACPI;
>+}
>+
> static int __init override_reboot(struct dmi_system_id *d)
> {
>     enum reboot_type type = (long)d->driver_data;
>@@ -452,6 +464,7 @@ static struct dmi_system_id __initdata r
> 
> static int __init reboot_init(void)
> {
>+    default_reboot_type();
>     dmi_check_system(reboot_dmi_table);
>     return 0;
> }
>@@ -465,7 +478,7 @@ static void noreturn __machine_restart(v
> void machine_restart(unsigned int delay_millisecs)
> {
>     unsigned int i, attempt;
>-    enum reboot_type orig_reboot_type = reboot_type;
>+    enum reboot_type orig_reboot_type;
>     const struct desc_ptr no_idt = { 0 };
> 
>     watchdog_disable();
>@@ -504,15 +517,20 @@ void machine_restart(unsigned int delay_
>         tboot_shutdown(TB_SHUTDOWN_REBOOT);
>     }
> 
>-    efi_reset_system(reboot_mode != 0);
>+    /* Just in case reboot_init() didn't run yet. */
>+    default_reboot_type();
>+    orig_reboot_type = reboot_type;
> 
>     /* Rebooting needs to touch the page at absolute address 0. */
>-    *((unsigned short *)__va(0x472)) = reboot_mode;
>+    if ( reboot_type != BOOT_EFI )
>+        *((unsigned short *)__va(0x472)) = reboot_mode;
> 
>     for ( attempt = 0; ; attempt++ )
>     {
>         switch ( reboot_type )
>         {
>+        case BOOT_INVALID:
>+            ASSERT_UNREACHABLE();
>         case BOOT_KBD:
>             /* Pulse the keyboard reset line. */
>             for ( i = 0; i < 100; i++ )
>@@ -532,6 +550,11 @@ void machine_restart(unsigned int delay_
>     reboot_type = (((attempt == 1) && (orig_reboot_type == BOOT_ACPI))
>                            ? BOOT_ACPI : BOOT_TRIPLE);
>             break;
>+        case BOOT_EFI:
>+            efi_reset_system(reboot_mode != 0);
>+            reboot_type = acpi_disabled ? BOOT_KBD : BOOT_ACPI;
>+            *((unsigned short *)__va(0x472)) = reboot_mode;
>+            break;
>         case BOOT_TRIPLE:
>             asm volatile ("lidt %0; int3" : : "m" (no_idt));
>             reboot_type = BOOT_KBD;



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