Re: [PATCH 1/2] pvpanic: introduce crashloaded for pvpanic

[Paolo Bonzini]

On 14/01/20 03:31, zhenwei pi wrote:
> Add bit 1 for pvpanic. This bit means that guest hits a panic, but
> guest wants to handle error by itself. Typical case: Linux guest runs
> kdump in panic. It will help us to separate the abnormal reboot from
> normal operation.
> 
> Signed-off-by: zhenwei pi <address@hidden>
> ---
>  docs/specs/pvpanic.txt | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/specs/pvpanic.txt b/docs/specs/pvpanic.txt
> index c7bbacc778..bdea68a430 100644
> --- a/docs/specs/pvpanic.txt
> +++ b/docs/specs/pvpanic.txt
> @@ -16,8 +16,12 @@ pvpanic exposes a single I/O port, by default 0x505. On 
> read, the bits
>  recognized by the device are set. Software should ignore bits it doesn't
>  recognize. On write, the bits not recognized by the device are ignored.
>  Software should set only bits both itself and the device recognize.
> -Currently, only bit 0 is recognized, setting it indicates a guest panic
> -has happened.
> +
> +Bit Definition
> +--------------
> +bit 0: setting it indicates a guest panic has happened.
> +bit 1: named crashloaded. setting it indicates a guest panic and run
> +       kexec to handle error by guest itself.
>  
>  ACPI Interface
>  --------------
> 

I added this:

@@ -30,13 +31,12 @@ pvpanic device is defined with ACPI ID "QEMU0001". Custom 
methods:
 
 RDPT:       To determine whether guest panic notification is supported.
 Arguments:  None
-Return:     Returns a byte, bit 0 set to indicate guest panic
-            notification is supported. Other bits are reserved and
-            should be ignored.
+Return:     Returns a byte, with the same semantics as the I/O port
+            interface.
 
 WRPT:       To send a guest panic event
-Arguments:  Arg0 is a byte, with bit 0 set to indicate guest panic has
-            happened. Other bits are reserved and should be cleared.
+Arguments:  Arg0 is a byte to be written, with the same semantics as
+            the I/O interface.
 Return:     None
 
 The ACPI device will automatically refer to the right port in case it


Paolo