Re: [PATCH v2 04/70] x86/pv-shim: Don't modify the hypercall table

[Andrew Cooper <amc96@xxxxxxxx>]

On 14/02/2022 13:33, Jan Beulich wrote:
> On 14.02.2022 13:50, Andrew Cooper wrote:
>> From: Juergen Gross <jgross@xxxxxxxx>
>>
>> When running as pv-shim the hypercall is modified today in order to
>> replace the functions for __HYPERVISOR_event_channel_op and
>> __HYPERVISOR_grant_table_op hypercalls.
>>
>> Change this to call the related functions from the normal handlers
>> instead when running as shim. The performance implications are not
>> really relevant, as a normal production hypervisor will not be
>> configured to support shim mode, so the related calls will be dropped
>> due to optimization of the compiler.
>>
>> Note that for the CONFIG_PV_SHIM_EXCLUSIVE case there is a dummy
>> wrapper do_grant_table_op() needed, as in this case grant_table.c
>> isn't being built.
>>
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> I don't think you sync-ed this with Jürgen's v3. There were only minor
> changes but having a stale version sent two months later isn't very
> nice.

I did resync.  What do you think is missing?

>
>> --- a/xen/common/compat/multicall.c
>> +++ b/xen/common/compat/multicall.c
>> @@ -5,7 +5,7 @@
>>  EMIT_FILE;
>>  
>>  #include <xen/types.h>
>> -#include <xen/multicall.h>
>> +#include <xen/hypercall.h>
>>  #include <xen/trace.h>
>>  
>>  #define COMPAT
>> @@ -19,7 +19,6 @@ static inline void xlat_multicall_entry(struct mc_state 
>> *mcs)
>>          mcs->compat_call.args[i] = mcs->call.args[i];
>>  }
>>  
>> -DEFINE_XEN_GUEST_HANDLE(multicall_entry_compat_t);
>>  #define multicall_entry      compat_multicall_entry
>>  #define multicall_entry_t    multicall_entry_compat_t
>>  #define do_multicall_call    compat_multicall_call
> Jürgen's patch doesn't have any change to this file, and I'm afraid I
> also don't see how these adjustments are related here. The commit
> message sadly also doesn't help ...

The changes are very necessary to split it out of Juergen's series.

Without the adjustment, the correction of compat_platform_op()'s guest
handle type from void to compat_platform_op_t doesn't compile.

~Andrew