From: Dave Hansen <dave.hansen@intel.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Joerg Roedel <jroedel@suse.de>, Ard Biesheuvel <ardb@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Tom Lendacky <thomas.lendacky@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Varad Gautam <varad.gautam@suse.com>,
Dario Faggioli <dfaggioli@suse.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Mike Rapoport <rppt@kernel.org>,
David Hildenbrand <david@redhat.com>,
x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv4 6/8] x86/mm: Provide helpers for unaccepted memory
Date: Fri, 8 Apr 2022 11:15:11 -0700 [thread overview]
Message-ID: <cfd834e2-60bb-78fb-b4a6-519ca173cd4a@intel.com> (raw)
In-Reply-To: <20220405234343.74045-7-kirill.shutemov@linux.intel.com>
On 4/5/22 16:43, Kirill A. Shutemov wrote:
> Core-mm requires few helpers to support unaccepted memory:
>
> - accept_memory() checks the range of addresses against the bitmap and
> accept memory if needed.
>
> - memory_is_unaccepted() check if anything within the range requires
> acceptance.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> arch/x86/include/asm/page.h | 5 +++
> arch/x86/include/asm/unaccepted_memory.h | 1 +
> arch/x86/mm/Makefile | 2 +
> arch/x86/mm/unaccepted_memory.c | 53 ++++++++++++++++++++++++
> 4 files changed, 61 insertions(+)
> create mode 100644 arch/x86/mm/unaccepted_memory.c
>
> diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
> index 9cc82f305f4b..9ae0064f97e5 100644
> --- a/arch/x86/include/asm/page.h
> +++ b/arch/x86/include/asm/page.h
> @@ -19,6 +19,11 @@
> struct page;
>
> #include <linux/range.h>
> +
> +#ifdef CONFIG_UNACCEPTED_MEMORY
> +#include <asm/unaccepted_memory.h>
> +#endif
It's a lot nicer to just to the #ifdefs inside the header. Is there a
specific reason to do it this way?
> extern struct range pfn_mapped[];
> extern int nr_pfn_mapped;
>
> diff --git a/arch/x86/include/asm/unaccepted_memory.h b/arch/x86/include/asm/unaccepted_memory.h
> index f1f835d3cd78..a8d12ef1bda8 100644
> --- a/arch/x86/include/asm/unaccepted_memory.h
> +++ b/arch/x86/include/asm/unaccepted_memory.h
> @@ -10,5 +10,6 @@ struct boot_params;
> void mark_unaccepted(struct boot_params *params, u64 start, u64 num);
>
> void accept_memory(phys_addr_t start, phys_addr_t end);
> +bool memory_is_unaccepted(phys_addr_t start, phys_addr_t end);
>
> #endif
> diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
> index fe3d3061fc11..e327f83e6bbf 100644
> --- a/arch/x86/mm/Makefile
> +++ b/arch/x86/mm/Makefile
> @@ -60,3 +60,5 @@ obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_amd.o
>
> obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_identity.o
> obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_boot.o
> +
> +obj-$(CONFIG_UNACCEPTED_MEMORY) += unaccepted_memory.o
> diff --git a/arch/x86/mm/unaccepted_memory.c b/arch/x86/mm/unaccepted_memory.c
> new file mode 100644
> index 000000000000..3588a7cb954c
> --- /dev/null
> +++ b/arch/x86/mm/unaccepted_memory.c
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include <linux/memblock.h>
> +#include <linux/mm.h>
> +#include <linux/pfn.h>
> +#include <linux/spinlock.h>
> +
> +#include <asm/io.h>
> +#include <asm/setup.h>
> +#include <asm/unaccepted_memory.h>
> +
> +static DEFINE_SPINLOCK(unaccepted_memory_lock);
We need some documentation on what the lock does, either here or in the
changelog.
> +void accept_memory(phys_addr_t start, phys_addr_t end)
> +{
> + unsigned long *unaccepted_memory;
> + unsigned long flags;
> + unsigned int rs, re;
> +
> + if (!boot_params.unaccepted_memory)
> + return;
> +
> + unaccepted_memory = __va(boot_params.unaccepted_memory);
> + rs = start / PMD_SIZE;
> +
> + spin_lock_irqsave(&unaccepted_memory_lock, flags);
> + for_each_set_bitrange_from(rs, re, unaccepted_memory,
> + DIV_ROUND_UP(end, PMD_SIZE)) {
> + /* Platform-specific memory-acceptance call goes here */
> + panic("Cannot accept memory");
> + bitmap_clear(unaccepted_memory, rs, re - rs);
> + }
> + spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
> +}
That panic() is making me nervous. Is this bisect-safe? Is it safe
because there are no callers of this function yet?
> +bool memory_is_unaccepted(phys_addr_t start, phys_addr_t end)
> +{
> + unsigned long *unaccepted_memory = __va(boot_params.unaccepted_memory);
> + unsigned long flags;
> + bool ret = false;
> +
> + spin_lock_irqsave(&unaccepted_memory_lock, flags);
> + while (start < end) {
> + if (test_bit(start / PMD_SIZE, unaccepted_memory)) {
> + ret = true;
> + break;
> + }
> +
> + start += PMD_SIZE;
> + }
> + spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
> +
> + return ret;
> +}
next prev parent reply other threads:[~2022-04-08 18:15 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 23:43 [PATCHv4 0/8] mm, x86/cc: Implement support for unaccepted memory Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 1/8] mm: Add " Kirill A. Shutemov
2022-04-08 18:55 ` Dave Hansen
2022-04-09 15:54 ` Kirill A. Shutemov
2022-04-11 6:38 ` Dave Hansen
2022-04-11 10:07 ` Mike Rapoport
2022-04-13 11:40 ` Kirill A. Shutemov
2022-04-13 14:48 ` Mike Rapoport
2022-04-13 15:15 ` Kirill A. Shutemov
2022-04-13 20:06 ` Mike Rapoport
2022-04-11 8:47 ` David Hildenbrand
2022-04-08 19:04 ` David Hildenbrand
2022-04-08 19:11 ` Dave Hansen
2022-04-09 17:52 ` Kirill A. Shutemov
2022-04-11 6:41 ` Dave Hansen
2022-04-11 15:55 ` Borislav Petkov
2022-04-11 16:27 ` Dave Hansen
2022-04-11 18:55 ` Tom Lendacky
2022-04-12 8:15 ` David Hildenbrand
2022-04-12 16:08 ` Dave Hansen
2022-04-13 10:36 ` David Hildenbrand
2022-04-13 11:30 ` Kirill A. Shutemov
2022-04-13 11:32 ` David Hildenbrand
2022-04-13 15:36 ` Dave Hansen
2022-04-13 16:07 ` David Hildenbrand
2022-04-13 16:13 ` Dave Hansen
2022-04-13 16:24 ` Kirill A. Shutemov
2022-04-13 14:39 ` Mike Rapoport
2022-04-05 23:43 ` [PATCHv4 2/8] efi/x86: Get full memory map in allocate_e820() Kirill A. Shutemov
[not found] ` <Ylae+bejPzRMPrDw@zn.tnic>
2022-04-13 11:45 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 3/8] efi/x86: Implement support for unaccepted memory Kirill A. Shutemov
2022-04-08 17:26 ` Dave Hansen
2022-04-09 19:41 ` Kirill A. Shutemov
2022-04-14 15:55 ` Borislav Petkov
2022-04-15 22:24 ` Borislav Petkov
2022-04-18 15:55 ` Kirill A. Shutemov
2022-04-18 16:38 ` Borislav Petkov
2022-04-18 20:24 ` Kirill A. Shutemov
2022-04-18 21:01 ` Borislav Petkov
2022-04-18 23:50 ` Kirill A. Shutemov
2022-04-19 7:39 ` Borislav Petkov
2022-04-19 15:30 ` Kirill A. Shutemov
2022-04-19 16:38 ` Dave Hansen
2022-04-19 19:23 ` Borislav Petkov
2022-04-21 12:26 ` Borislav Petkov
2022-04-22 0:21 ` Kirill A. Shutemov
2022-04-22 9:30 ` Borislav Petkov
2022-04-22 13:26 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 4/8] x86/boot/compressed: Handle " Kirill A. Shutemov
2022-04-08 17:57 ` Dave Hansen
2022-04-09 20:20 ` Kirill A. Shutemov
2022-04-11 6:49 ` Dave Hansen
2022-04-05 23:43 ` [PATCHv4 5/8] x86/mm: Reserve unaccepted memory bitmap Kirill A. Shutemov
2022-04-08 18:08 ` Dave Hansen
2022-04-09 20:43 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 6/8] x86/mm: Provide helpers for unaccepted memory Kirill A. Shutemov
2022-04-08 18:15 ` Dave Hansen [this message]
2022-04-08 19:21 ` Dave Hansen
2022-04-13 16:08 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 7/8] x86/tdx: Unaccepted memory support Kirill A. Shutemov
2022-04-08 18:28 ` Dave Hansen
2022-04-05 23:43 ` [PATCHv4 8/8] mm/vmstat: Add counter for memory accepting Kirill A. Shutemov
2022-04-12 8:18 ` David Hildenbrand
2022-04-08 17:02 ` [PATCHv4 0/8] mm, x86/cc: Implement support for unaccepted memory Dave Hansen
2022-04-09 23:44 ` Kirill A. Shutemov
2022-04-21 12:29 ` Borislav Petkov
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