question about mmu.

question about mmu.

[cs-jerry**]

hi all,
     if gpte in guest table was set write protection , the corresponding spte in shadow will set be write protection. so any operation in guest trying to
modify guest page will generate page fault to stop the opetation except on condition that the guest set  wp bit in cr0. so  my question is, how to make sure the guest is not able  to modify  specified page,considering the condition that wp bit in cr0 will be set to 0? 
thanks.

Re: question about mmu.

[Xiao Guangrong]

On 08/30/2010 02:07 PM, cs-jerry** wrote:
> hi all,
>      if gpte in guest table was set write protection , the corresponding spte in shadow will set be write protection. so any operation in guest trying to
> modify guest page will generate page fault to stop the opetation except on condition that the guest set  wp bit in cr0. so  my question is, how to make sure the guest is not able  to modify  specified page,considering the condition that wp bit in cr0 will be set to 0? 
> thanks.N‹§²æìr¸›yúèšØb²X¬¶Ç§vØ^–)Þº{.nÇ+‰·¤¾h§¶\x17›¡Ü¨}©ž²Æ zÚ&j:+v‰¨¾\a«‘êçzZ+€Ê+zf£¢·hšˆ§~†­†Ûiÿûàz¹\x1e®w¥¢¸?™¨è­Ú&¢)ߢ^[fl===

See commit: e52d8d2d5dffbaee5176a0460f3e9883fb686ac0

1: if it's write #PF, we set spte.w but remove spte.u, then
2: if user access, if will cause read #PF, it will set spte.w = 0 and spte.u = 1