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Date:   Mon, 21 Oct 2019 20:22:07 -0700
From:   Sean Christopherson <sean.j.christopherson@intel.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc:     linux-sgx@vger.kernel.org
Subject: Re: [PATCH for_v23 v3 01/12] x86/sgx: Pass EADD the kernel's virtual
 address for the source page
Message-ID: <20191022032207.GC32147@linux.intel.com>
References: <20191016183745.8226-1-sean.j.christopherson@intel.com>
 <20191016183745.8226-2-sean.j.christopherson@intel.com>
 <20191018095713.GA4835@linux.intel.com>
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On Fri, Oct 18, 2019 at 12:57:13PM +0300, Jarkko Sakkinen wrote:
> On Wed, Oct 16, 2019 at 11:37:34AM -0700, Sean Christopherson wrote:
> > Use the kernel's virtual address to reference the source page when
> > EADDing a page to the enclave.  gup() "does not guarantee that the page
> > exists in the user mappings", i.e. EADD can still fault and deadlock
> > due to mmap_sem contention if it consumes the userspace address.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > +	kunmap_atomic((void *)pginfo.contents);
> 
> Remark: if not casted first to unsigned long,  it will give a warning on
> 32-bit build.

Do we care?  SGX is 64-bit only, I don't see that changing anytime soon.