> -----Original Message-----
> From: Christopherson, Sean J
> Sent: Monday, June 03, 2019 1:37 PM
> To: Hansen, Dave <dave.hansen@xxxxxxxxx>
> Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>; Andy Lutomirski
> <luto@xxxxxxxxxx>; Xing, Cedric <cedric.xing@xxxxxxxxx>; Stephen Smalley
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> Paul Moore <paul@xxxxxxxxxxxxxx>; Eric Paris <eparis@xxxxxxxxxxxxxx>;
> selinux@xxxxxxxxxxxxxxx; Jethro Beekman <jethro@xxxxxxxxxxxx>; Thomas
> Gleixner <tglx@xxxxxxxxxxxxx>; Linus Torvalds <torvalds@linux-
> foundation.org>; LKML <linux-kernel@xxxxxxxxxxxxxxx>; X86 ML
> <x86@xxxxxxxxxx>; linux-sgx@xxxxxxxxxxxxxxx; Andrew Morton <akpm@linux-
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> Borislav Petkov <bp@xxxxxxxxx>; Josh Triplett <josh@xxxxxxxxxxxxxxxx>;
> Huang, Kai <kai.huang@xxxxxxxxx>; David Rientjes <rientjes@xxxxxxxxxx>;
> Roberts, William C <william.c.roberts@xxxxxxxxx>; Tricca, Philip B
> <philip.b.tricca@xxxxxxxxx>
> Subject: Re: [RFC PATCH 3/9] x86/sgx: Allow userspace to add multiple
> pages in single ioctl()
>
> On Mon, Jun 03, 2019 at 01:14:45PM -0700, Dave Hansen wrote:
> > On 5/31/19 4:31 PM, Sean Christopherson wrote:
> > > -struct sgx_enclave_add_page {
> > > +struct sgx_enclave_add_pages {
> > > __u64 addr;
> > > __u64 src;
> > > __u64 secinfo;
> > > + __u32 nr_pages;
> > > __u16 mrmask;
> > > } __attribute__((__packed__));
> >
> > IMNHO this follows a user interface anti-pattern: exposing page sizes
> > where not strictly required.
> >
> > Think of how this would look to an application if page size was
> > variable. With this interface, they always need to scale their
> > operations by page size instead of just aligning it.
>
> I briefly considered taking size in bytes, but I took a shortcut because
> EPC pages are architecturally defined to be 4k sized and aligned. That
> being said, I don't necessarily disagree, especially if nr_pages isn't
> squeezed into a u32.
>
> > BTW, why is nr_pages a u32? Do we never envision a case where you can
> > add more than 4TB of memory to an enclave? ;)
>
> Heh, fair enough. IIRC, a while back someone posted about having
> problems building a 512gb enclave in a 92mb EPC...
>
> How about this for the intermediate patch:
>
> struct sgx_enclave_add_region {
> __u64 addr;
> __u64 src;
> __u64 size;
> __u64 secinfo;
> __u16 mrmask;
> __u16 reserved16;
> __u32 reserved;
> }
>
> and with the flags field:
>
> struct sgx_enclave_add_region {
> __u64 addr;
> __u64 src;
> __u64 size;
> __u64 secinfo;
> __u16 mrmask;
> __u16 flags;
What is "flags" here?
> __u32 reserved;
> }
