Re: [PATCH 2/3] add SPTE_HOST_WRITEABLE flag to the shadow ptes

[Izik Eidus <ieidus@redhat.com>]

Marcelo Tosatti wrote:
> On Thu, Sep 10, 2009 at 07:38:57PM +0300, Izik Eidus wrote:
>   
>> this flag notify that the host physical page we are pointing to from
>> the spte is write protected, and therefore we cant change its access
>> to be write unless we run get_user_pages(write = 1).
>>
>> (this is needed for change_pte support in kvm)
>>
>> Signed-off-by: Izik Eidus <ieidus@redhat.com>
>> ---
>>  arch/x86/kvm/mmu.c         |   15 +++++++++++----
>>  arch/x86/kvm/paging_tmpl.h |   18 +++++++++++++++---
>>  2 files changed, 26 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index 62d2f86..a7151b8 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -156,6 +156,8 @@ module_param(oos_shadow, bool, 0644);
>>  #define CREATE_TRACE_POINTS
>>  #include "mmutrace.h"
>>  
>> +#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
>> +
>>  #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
>>  
>>  struct kvm_rmap_desc {
>> @@ -1754,7 +1756,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
>>  		    unsigned pte_access, int user_fault,
>>  		    int write_fault, int dirty, int level,
>>  		    gfn_t gfn, pfn_t pfn, bool speculative,
>> -		    bool can_unsync)
>> +		    bool can_unsync, bool reset_host_protection)
>>     
> 				     bool host_pte_writeable ?
>
>   
>
Sure.