On Tue, Apr 26, 2016 at 11:49:38PM -0700, Jethro Beekman wrote:
> On 25-04-16 10:34, Jarkko Sakkinen wrote:
> > diff --git a/drivers/staging/intel_sgx/isgx_ioctl.c
> b/drivers/staging/intel_sgx/isgx_ioctl.c
> > new file mode 100644
> > index 0000000..9d8b36b
> > --- /dev/null
> > +++ b/drivers/staging/intel_sgx/isgx_ioctl.c
> >
> > +static long isgx_ioctl_enclave_create(struct file *filep, unsigned int cmd,
> > + unsigned long arg)
> >
> > + secs->base = vm_mmap(filep, 0, secs->size,
> > + PROT_READ | PROT_WRITE | PROT_EXEC,
> > + MAP_SHARED, 0);
>
> Why does the ioctl interface map userspace memory for an open device?
> There's already a perfectly good syscall for that: mmap.
You didn't explain what would be the value in doing this but after
thinking for a short while I found out two good reasons:
* The current API is ugly in a way that you can anyway call mmap
directly too and have a useless zombie enclave. This would make
the API less ambiguous.
* SGX_IOC_ENCLAVE_CREATE could be removed. SECS could be passed
through SGX_IOC_ENCLAVE_ADD_PAGE thus simplifying the API a lot.
Given these circumstances I think this does make sense.
> > diff --git a/drivers/staging/intel_sgx/isgx_user.h
> > b/drivers/staging/intel_sgx/isgx_user.h
> > new file mode 100644
> > index 0000000..672d19c
> > --- /dev/null
> > +++ b/drivers/staging/intel_sgx/isgx_user.h
> >
> > +#define SGX_ADD_SKIP_EEXTEND 0x1
> > +
> > +struct sgx_add_param {
> > + unsigned long addr;
> > + unsigned long user_addr;
> > + struct isgx_secinfo *secinfo;
> > + unsigned int flags;
> > +};
>
> The hardware supports calling EEXTEND on only a part of a page, I think the
> driver should also support that.
Why would you want to do that?
> Jethro
/Jarkko
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