Re: [Xen-devel] [PATCH v2 09/12] x86/altp2m: add remaining support routines.

[Ed White <edmund.h.white@xxxxxxxxx>]

On 06/23/2015 11:15 AM, Lengyel, Tamas wrote:
> On Mon, Jun 22, 2015 at 2:56 PM, Ed White <edmund.h.white@xxxxxxxxx> wrote:
> 
>> Add the remaining routines required to support enabling the alternate
>> p2m functionality.
>>
>> Signed-off-by: Ed White <edmund.h.white@xxxxxxxxx>
>> ---
>>  xen/arch/x86/hvm/hvm.c              |  60 +++++-
>>  xen/arch/x86/mm/hap/Makefile        |   1 +
>>  xen/arch/x86/mm/hap/altp2m_hap.c    | 103 +++++++++
>>  xen/arch/x86/mm/p2m-ept.c           |   3 +
>>  xen/arch/x86/mm/p2m.c               | 405
>> ++++++++++++++++++++++++++++++++++++
>>  xen/include/asm-x86/hvm/altp2mhvm.h |   4 +
>>  xen/include/asm-x86/p2m.h           |  33 +++
>>  7 files changed, 601 insertions(+), 8 deletions(-)
>>  create mode 100644 xen/arch/x86/mm/hap/altp2m_hap.c
>>
>> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
>> index d75c12d..b758ee1 100644
>> --- a/xen/arch/x86/hvm/hvm.c
>> +++ b/xen/arch/x86/hvm/hvm.c
>> @@ -2786,10 +2786,11 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
>> unsigned long gla,
>>      p2m_access_t p2ma;
>>      mfn_t mfn;
>>      struct vcpu *v = current;
>> -    struct p2m_domain *p2m;
>> +    struct p2m_domain *p2m, *hostp2m;
>>      int rc, fall_through = 0, paged = 0;
>>      int sharing_enomem = 0;
>>      vm_event_request_t *req_ptr = NULL;
>> +    int altp2m_active = 0;
>>
>>      /* On Nested Virtualization, walk the guest page table.
>>       * If this succeeds, all is fine.
>> @@ -2845,15 +2846,33 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
>> unsigned long gla,
>>      {
>>          if ( !handle_mmio_with_translation(gla, gpa >> PAGE_SHIFT, npfec)
>> )
>>              hvm_inject_hw_exception(TRAP_gp_fault, 0);
>> -        rc = 1;
>> -        goto out;
>> +        return 1;
>>      }
>>
>> -    p2m = p2m_get_hostp2m(v->domain);
>> -    mfn = get_gfn_type_access(p2m, gfn, &p2mt, &p2ma,
>> +    altp2m_active = altp2mhvm_active(v->domain);
>> +
>> +    /* Take a lock on the host p2m speculatively, to avoid potential
>> +     * locking order problems later and to handle unshare etc.
>> +     */
>> +    hostp2m = p2m_get_hostp2m(v->domain);
>> +    mfn = get_gfn_type_access(hostp2m, gfn, &p2mt, &p2ma,
>>                                P2M_ALLOC | (npfec.write_access ?
>> P2M_UNSHARE : 0),
>>                                NULL);
>>
>> +    if ( altp2m_active )
>> +    {
>> +        if ( altp2mhvm_hap_nested_page_fault(v, gpa, gla, npfec, &p2m) ==
>> 1 )
>> +        {
>> +            /* entry was lazily copied from host -- retry */
>> +            __put_gfn(hostp2m, gfn);
>> +            return 1;
>> +        }
>> +
>> +        mfn = get_gfn_type_access(p2m, gfn, &p2mt, &p2ma, 0, NULL);
>> +    }
>> +    else
>> +        p2m = hostp2m;
>> +
>>      /* Check access permissions first, then handle faults */
>>      if ( mfn_x(mfn) != INVALID_MFN )
>>      {
>> @@ -2893,6 +2912,20 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
>> long gla,
>>
>>          if ( violation )
>>          {
>> +            /* Should #VE be emulated for this fault? */
>> +            if ( p2m_is_altp2m(p2m) && !cpu_has_vmx_virt_exceptions )
>> +            {
>> +                unsigned int sve;
>> +
>> +                p2m->get_entry_full(p2m, gfn, &p2mt, &p2ma, 0, NULL,
>> &sve);
>> +
>> +                if ( !sve && ahvm_vcpu_emulate_ve(v) )
>>
> 
> This line generates the following compile-time error: "hvm.c:2923:51:
> error: âvâ undeclared (first use in this function)". Did you mean to pass
> curr to ahvm_vcpu_emulate_ve instead of v?
> 
> I would recommend doing a compile-test on each patch of the series to catch
> small things like this. Travis-ci has been working really great for me to
> automate that process (https://github.com/tklengyel/xen/compare/travis) ;)
> 

I don't know why you are seeing that error, you can clearly see that v is
defined and initialised at the start of the containing function, and has
been used earlier.

I always compile test every patch individually.

Ed


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