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From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "rppt@kernel.org" <rppt@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"keescook@chromium.org" <keescook@chromium.org>,
	"Weiny, Ira" <ira.weiny@intel.com>,
	"linux-hardening@vger.kernel.org"
	<linux-hardening@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"vbabka@suse.cz" <vbabka@suse.cz>,
	"x86@kernel.org" <x86@kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	"Lutomirski, Andy" <luto@kernel.org>,
	"kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	"shakeelb@google.com" <shakeelb@google.com>
Subject: Re: [RFC PATCH v2 17/19] x86/mm/cpa: PKS protect direct map page tables
Date: Tue, 31 Aug 2021 17:58:04 +0000	[thread overview]
Message-ID: <69aaf7209a560b6414c5ea839bd9a3800495050e.camel@intel.com> (raw)
In-Reply-To: <YS4A+F1H9MvyOeMV@kernel.org>

On Tue, 2021-08-31 at 13:14 +0300, Mike Rapoport wrote:
trim
> > +/*
> > + * If pre boot, reserve large pages from memory that will be
> > mapped. It's ok that this is not
> > + * mapped as PKS, other init code in CPA will handle the
> > conversion.
> > + */
> > +static unsigned int __init reserve_pre_boot(u64 start, u64 end)
> > +{
> > +     u64 cur = memblock_find_in_range(start, end, HPAGE_SIZE,
> > HPAGE_SIZE);
> > +     int i;
> 
> Please use memblock_phys_alloc_range() here.
Oh yea, that's better. Thanks.

> Besides, it seems this reserved pages are not accessed until
> late_initcall
> time, so there is no need to limit the allocation to already mapped
> areas,
> memblock_alloc_raw() would suffice.
The page itself is used for the llist_node. I didn't see an easy way to
get a smaller allocate at this time. I guess it could use less mapped
memory by just using a few mapped pages for some structs to keep the
list outside of the unmapped pages, but it becomes more complex.

> 
> > +
> > +     if (!cur)
> > +             return 0;
> > +     memblock_reserve(cur, HPAGE_SIZE);
> > +     for (i = 0; i < HPAGE_SIZE; i += PAGE_SIZE)
> > +             add_dmap_table((unsigned long)__va(cur + i));
> > +     return HPAGE_SIZE;
> > +}
> > +
> > +/* If post boot, memblock is not available. Just reserve from
> > other memory regions */
> > +static unsigned int __init reserve_post_boot(void)
> > +{
> > +     struct page *page = alloc_table(GFP_KERNEL);
> > +
> > +     if (!page)
> > +             return 0;
> > +
> > +     add_dmap_table((unsigned long)page_address(page));
> 
> add_dmap_table() calls use casting everywhere, maybe make it
> add_dmap_table(void *)?
> 
Yea, I'll give it a try. It was on my todo list, but somehow got
forgotten.

> > +

  reply	other threads:[~2021-08-31 18:40 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-30 23:59 [RFC PATCH v2 00/19] PKS write protected " Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 01/19] list: Support getting most recent element in list_lru Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 02/19] list: Support list head not in object for list_lru Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 03/19] x86/mm/cpa: Add grouped page allocations Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 04/19] mm: Explicitly zero page table lock ptr Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 05/19] x86, mm: Use cache of page tables Rick Edgecombe
2021-08-31  8:40   ` Mike Rapoport
2021-08-31 19:09     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 06/19] x86/mm/cpa: Add perm callbacks to grouped pages Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 07/19] x86/cpufeatures: Add feature for pks tables Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 08/19] x86/mm/cpa: Add get_grouped_page_atomic() Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 09/19] x86/mm: Support GFP_ATOMIC in alloc_table_node() Rick Edgecombe
2021-08-31  8:32   ` Mike Rapoport
2021-08-30 23:59 ` [RFC PATCH v2 10/19] x86/mm: Use alloc_table() for fill_pte(), etc Rick Edgecombe
2021-08-31  8:47   ` Mike Rapoport
2021-08-31 18:48     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 11/19] mm/sparsemem: Use alloc_table() for table allocations Rick Edgecombe
2021-08-31  8:55   ` Mike Rapoport
2021-08-31 18:25     ` Edgecombe, Rick P
2021-09-01  7:22       ` Mike Rapoport
2021-09-02 13:56         ` Vlastimil Babka
2021-08-30 23:59 ` [RFC PATCH v2 12/19] x86/mm: Use free_table in unmap path Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 13/19] mm/debug_vm_page_table: Use setters instead of WRITE_ONCE Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 14/19] x86/efi: Toggle table protections when copying Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 15/19] x86/mm/cpa: Add set_memory_pks() Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 16/19] x86/mm: Protect page tables with PKS Rick Edgecombe
2021-08-31  8:56   ` Mike Rapoport
2021-08-31 17:55     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 17/19] x86/mm/cpa: PKS protect direct map page tables Rick Edgecombe
2021-08-31 10:14   ` Mike Rapoport
2021-08-31 17:58     ` Edgecombe, Rick P [this message]
2021-08-30 23:59 ` [RFC PATCH v2 18/19] x86/mm: Add PKS table soft mode Rick Edgecombe
2021-08-31  3:49   ` Randy Dunlap
2021-08-31 17:55     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 19/19] x86/mm: Add PKS table debug checking Rick Edgecombe

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