Re: [PATCH for v24 1/3] x86/sgx: Use GFP_KERNEL for allocations

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Mon, Nov 04, 2019 at 12:46:02PM -0800, Sean Christopherson wrote:
> On Mon, Nov 04, 2019 at 10:01:39PM +0200, Jarkko Sakkinen wrote:
> > The reasoning is the same as in
> > 
> > http://git.infradead.org/users/jjs/linux-tpmdd.git/commit/abd55954f91a3aacc1d260d2411cf776ec4d5fd2
> > 
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> >  arch/x86/kernel/cpu/sgx/ioctl.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> > index 5b28a9c0cb68..d53aee5a64c1 100644
> > --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> > @@ -259,7 +259,7 @@ static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
> >  	if (copy_from_user(&ecreate, arg, sizeof(ecreate)))
> >  		return -EFAULT;
> >  
> > -	secs_page = alloc_page(GFP_HIGHUSER);
> > +	secs_page = alloc_page(GFP_KERNEL);
> >  	if (!secs_page)
> >  		return -ENOMEM;
> >  
> > @@ -674,7 +674,7 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
> >  	if (copy_from_user(&einit, arg, sizeof(einit)))
> >  		return -EFAULT;
> >  
> > -	initp_page = alloc_page(GFP_HIGHUSER);
> > +	initp_page = alloc_page(GFP_KERNEL);
> 
> Would it make sense to use GFP_KERNEL_ACCOUNT?  The accounting would be
> weird for the case where userspace is using a builder process, but even in
> that case it's not flat out wrong to account per-enclave memory allocations.

I did not find a single call site that would use that for allocating
memory for function-internal data.

/Jarkko