On 08/06/2016 03:36 PM, Julien Grall wrote: > > > On 06/08/2016 10:54, Sergej Proskurin wrote: >> Hi Julien, > > Hello Sergej, > >> On 08/04/2016 01:46 PM, Julien Grall wrote: >>> Hello Sergej, >>> >>> On 01/08/16 18:10, Sergej Proskurin wrote: >>>> Signed-off-by: Sergej Proskurin <prosku...@sec.in.tum.de> >>>> --- >>>> Cc: Stefano Stabellini <sstabell...@kernel.org> >>>> Cc: Julien Grall <julien.gr...@arm.com> >>>> --- >>>> v2: Substituted the call to tlb_flush for p2m_flush_table. >>>> Added comments. >>>> Cosmetic fixes. >>>> --- >>>> xen/arch/arm/altp2m.c | 50 >>>> ++++++++++++++++++++++++++++++++++++++++++++ >>>> xen/arch/arm/hvm.c | 2 +- >>>> xen/include/asm-arm/altp2m.h | 4 ++++ >>>> 3 files changed, 55 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/xen/arch/arm/altp2m.c b/xen/arch/arm/altp2m.c >>>> index c22d2e4..80ed553 100644 >>>> --- a/xen/arch/arm/altp2m.c >>>> +++ b/xen/arch/arm/altp2m.c > > [...] > >>>> + >>>> + p2m_flush_table(p2m); >>>> + >>>> + /* >>>> + * Reset VTTBR. >>>> + * >>>> + * Note that VMID is not freed so that it can be reused >>>> later. >>>> + */ >>>> + p2m->vttbr.vttbr = INVALID_VTTBR; >>>> + d->arch.altp2m_vttbr[idx] = INVALID_VTTBR; >>>> + >>>> + read_unlock(&p2m->lock); >>> >>> Why did you decide to reset the p2m rather than free it? The code >>> would be simpler with the latter. >>> >> >> * First, to be as similar to the x86 implementation as possible. >> * Second, simply to reuse already allocated p2m's without additional >> overhead. > > I don't really buy those arguments. The x86 implementation may not fit > the ARM model. Initializing a p2m on ARM is very quick: allocating the > p2m and the root pages (up to 2 page). > > So the overhead is really minimal. Therefore, I don't see any reason > to introduce complex bookkeeping when NULL can be used for the same > purpose. >
Alright, I will adjust the implementation accordingly. Thank you. Best regards, ~Sergej _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
