From: Matthew Wilcox <willy@infradead.org>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
x86@kernel.org, linux-sgx@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Jethro Beekman <jethro@fortanix.com>,
Haitao Huang <haitao.huang@linux.intel.com>,
Chunyang Hui <sanqian.hcy@antfin.com>,
Jordan Hand <jorhand@linux.microsoft.com>,
Nathaniel McCallum <npmccallum@redhat.com>,
Seth Moore <sethmo@google.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
andriy.shevchenko@linux.intel.com, asapek@google.com,
bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com,
conradparker@google.com, cyhanish@google.com,
dave.hansen@intel.com, haitao.huang@intel.com,
josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com,
kmoy@google.com, ludloff@google.com, luto@kernel.org,
nhorman@redhat.com, puiterwijk@redhat.com, rientjes@google.com,
tglx@linutronix.de, yaozhangx@google.com
Subject: Re: [PATCH v34 11/24] x86/sgx: Add SGX enclave driver
Date: Tue, 7 Jul 2020 05:39:04 +0100 [thread overview]
Message-ID: <20200707043904.GJ25523@casper.infradead.org> (raw)
In-Reply-To: <20200707042904.GD5208@linux.intel.com>
On Mon, Jul 06, 2020 at 09:29:04PM -0700, Sean Christopherson wrote:
> > > > + idx_start = PFN_DOWN(start);
> > > > + idx_end = PFN_DOWN(end - 1);
> > > > +
> > > > + for (idx = idx_start; idx <= idx_end; ++idx) {
> > > > + mutex_lock(&encl->lock);
> > > > + page = radix_tree_lookup(&encl->page_tree, idx);
> > > > + mutex_unlock(&encl->lock);
> > > > +
> > > > + if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
> > > > + return -EACCES;
> > >
> > > You should really use an iterator here instead of repeated lookups.
> > > xas_for_each() will probably be what you want.
> >
> > Thank you for your remarks. I'll look into using xarray for this.
>
> Question for Matthew:
>
> To enforce the "page must be populated" rule, is there a clean way to retrieve
> the index of the current entry? Our entries/pages don't have information
> about their index. Or should we just count the number of entries and check
> 'em at the end? E.g.
>
> xas_for_each(...) {
> if (~page->vm_max_prot_bits & vm_prot_bits)
> return -EACCES;
> nr_entries++;
> }
>
> if (nr_entries != (end_index - start_index))
> return -EACCES;
Probably best just to steal the implementation from here:
pgoff_t page_cache_next_miss(struct address_space *mapping,
pgoff_t index, unsigned long max_scan)
{
XA_STATE(xas, &mapping->i_pages, index);
while (max_scan--) {
void *entry = xas_next(&xas);
if (!entry || xa_is_value(entry))
break;
if (xas.xa_index == 0)
break;
}
return xas.xa_index;
}
although I think you have a simpler task.
XA_STATE(xas, ..., start_index);
for (;;) {
struct page *page = xas_next(&xas);
if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
return -EACCES;
}
return 0;
should do the trick, I think.
next prev parent reply other threads:[~2020-07-07 4:39 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 3:01 [PATCH v34 00/24] Intel SGX foundations Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 10/24] mm: Add vm_ops->mprotect() Jarkko Sakkinen
2020-07-07 3:14 ` Matthew Wilcox
2020-07-07 3:22 ` Sean Christopherson
2020-07-07 3:24 ` Matthew Wilcox
2020-07-07 4:01 ` Jarkko Sakkinen
2020-07-07 4:10 ` Matthew Wilcox
2020-07-08 14:33 ` Jarkko Sakkinen
2020-07-08 14:37 ` Matthew Wilcox
2020-07-08 16:10 ` Jarkko Sakkinen
2020-07-08 22:56 ` Jarkko Sakkinen
2020-07-07 4:03 ` Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-07-07 3:36 ` Matthew Wilcox
2020-07-07 4:11 ` Jarkko Sakkinen
2020-07-07 4:29 ` Sean Christopherson
2020-07-07 4:39 ` Matthew Wilcox [this message]
2020-07-07 4:46 ` Sean Christopherson
2020-07-07 3:01 ` [PATCH v34 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-07-07 3:29 ` Sean Christopherson
2020-07-07 4:04 ` Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 15/24] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-07-07 3:01 ` [PATCH v34 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-07-07 3:02 ` [PATCH v34 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-07-07 3:02 ` [PATCH v34 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-07-07 3:02 ` [PATCH v34 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-07-07 3:02 ` [PATCH v34 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-07-07 3:02 ` [PATCH v34 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200707043904.GJ25523@casper.infradead.org \
--to=willy@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=andriy.shevchenko@linux.intel.com \
--cc=asapek@google.com \
--cc=bp@alien8.de \
--cc=cedric.xing@intel.com \
--cc=chenalexchen@google.com \
--cc=conradparker@google.com \
--cc=cyhanish@google.com \
--cc=dave.hansen@intel.com \
--cc=haitao.huang@intel.com \
--cc=haitao.huang@linux.intel.com \
--cc=jarkko.sakkinen@linux.intel.com \
--cc=jethro@fortanix.com \
--cc=jorhand@linux.microsoft.com \
--cc=josh@joshtriplett.org \
--cc=kai.huang@intel.com \
--cc=kai.svahn@intel.com \
--cc=kmoy@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-security-module@vger.kernel.org \
--cc=linux-sgx@vger.kernel.org \
--cc=ludloff@google.com \
--cc=luto@kernel.org \
--cc=nhorman@redhat.com \
--cc=npmccallum@redhat.com \
--cc=puiterwijk@redhat.com \
--cc=rientjes@google.com \
--cc=sanqian.hcy@antfin.com \
--cc=sean.j.christopherson@intel.com \
--cc=sethmo@google.com \
--cc=suresh.b.siddha@intel.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
--cc=yaozhangx@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).