Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-06 Thread Tamas K Lengyel
On Thu, Oct 6, 2016 at 11:10 AM, Julien Grall wrote: > > > On 06/10/2016 09:39, Tamas K Lengyel wrote: > >> >> >> On Thu, Oct 6, 2016 at 3:59 AM, Razvan Cojocaru >> mailto:rcojoc...@bitdefender.com>> wrote: >> >> On 10/05/2016 11:54 PM, Julien Grall wrote: >> > >> > >> > On 05/10/

Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-06 Thread Julien Grall
On 06/10/2016 09:39, Tamas K Lengyel wrote: On Thu, Oct 6, 2016 at 3:59 AM, Razvan Cojocaru mailto:rcojoc...@bitdefender.com>> wrote: On 10/05/2016 11:54 PM, Julien Grall wrote: > > > On 05/10/2016 13:23, Tamas K Lengyel wrote: >> Hi Julien, >> It is expected that cer

Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-06 Thread Tamas K Lengyel
On Thu, Oct 6, 2016 at 3:59 AM, Razvan Cojocaru wrote: > On 10/05/2016 11:54 PM, Julien Grall wrote: > > > > > > On 05/10/2016 13:23, Tamas K Lengyel wrote: > >> Hi Julien, > >> It is expected that certain combinations of mem_access flags will put > >> the domain into unstable condition, resultin

Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-06 Thread Razvan Cojocaru
On 10/05/2016 11:54 PM, Julien Grall wrote: > > > On 05/10/2016 13:23, Tamas K Lengyel wrote: >> Hi Julien, >> It is expected that certain combinations of mem_access flags will put >> the domain into unstable condition, resulting in a crash or a hang. As >> Razvan mentioned, on x86 we can end up

Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-05 Thread Julien Grall
On 05/10/2016 13:23, Tamas K Lengyel wrote: Hi Julien, It is expected that certain combinations of mem_access flags will put the domain into unstable condition, resulting in a crash or a hang. As Razvan mentioned, on x86 we can end up triggering EPT misconfiguration with the wrong set of flags.

Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-05 Thread Tamas K Lengyel
Hi Julien, It is expected that certain combinations of mem_access flags will put the domain into unstable condition, resulting in a crash or a hang. As Razvan mentioned, on x86 we can end up triggering EPT misconfiguration with the wrong set of flags. The user of the API is expected to know what he

Re: [Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-05 Thread Razvan Cojocaru
Hello Julien, > I have been looking into mem access support on ARM and I am wondering > how we expect the flags MEM_ACCESS_{R,W,X} to be used when the > permission fault is happening during stage 1 page table walk. > > For instance, if the fault is happening when the processor is loading an > ins

[Xen-devel] Clarification regarding MEM_ACCESS_* flags usage

2016-10-05 Thread Julien Grall
Hello Tamas and Ravzan, I have been looking into mem access support on ARM and I am wondering how we expect the flags MEM_ACCESS_{R,W,X} to be used when the permission fault is happening during stage 1 page table walk. For instance, if the fault is happening when the processor is loading an