From: Tom Lendacky <thomas.lendacky@amd.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>,
simon.guinot@sequanux.org, linux-efi@vger.kernel.org,
kvm@vger.kernel.org, rkrcmar@redhat.com,
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davem@davemloft.net
Subject: Re: [RFC PATCH v2 06/32] x86/pci: Use memremap when walking setup data
Date: Mon, 13 Mar 2017 15:08:52 -0500 [thread overview]
Message-ID: <a0c3ebb9-37b4-3f47-86df-eac110c07032@amd.com> (raw)
In-Reply-To: <20170307000349.GC5305@bhelgaas-glaptop.roam.corp.google.com>
On 3/6/2017 6:03 PM, Bjorn Helgaas wrote:
> On Fri, Mar 03, 2017 at 03:15:34PM -0600, Tom Lendacky wrote:
>> On 3/3/2017 2:42 PM, Bjorn Helgaas wrote:
>>> On Thu, Mar 02, 2017 at 10:13:10AM -0500, Brijesh Singh wrote:
>>>> From: Tom Lendacky <thomas.lendacky@amd.com>
>>>>
>>>> The use of ioremap will force the setup data to be mapped decrypted even
>>>> though setup data is encrypted. Switch to using memremap which will be
>>>> able to perform the proper mapping.
>>>
>>> How should callers decide whether to use ioremap() or memremap()?
>>>
>>> memremap() existed before SME and SEV, and this code is used even if
>>> SME and SEV aren't supported, so the rationale for this change should
>>> not need the decryption argument.
>>
>> When SME or SEV is active an ioremap() will remove the encryption bit
>> from the pagetable entry when it is mapped. This allows MMIO, which
>> doesn't support SME/SEV, to be performed successfully. So my take is
>> that ioremap() should be used for MMIO and memremap() for pages in RAM.
>
> OK, thanks. The commit message should say something like "this is
> RAM, not MMIO, so we should map it with memremap(), not ioremap()".
> That's the part that determines whether the change is correct.
>
> You can mention the encryption part, too, but it's definitely
> secondary because the change has to make sense on its own, without
> SME/SEV.
>
Ok, that makes sense, will do.
> The following commits (from https://github.com/codomania/tip/branches)
> all do basically the same thing so the changelogs (and summaries)
> should all be basically the same:
>
> cb0d0d1eb0a6 x86: Change early_ioremap to early_memremap for BOOT data
> 91acb68b8333 x86/pci: Use memremap when walking setup data
> 4f687503e23f x86: Access the setup data through sysfs decrypted
> e90246b8c229 x86: Access the setup data through debugfs decrypted
>
> I would collect them all together and move them to the beginning of
> your series, since they don't depend on anything else.
I'll do that.
>
> Also, change "x86/pci: " to "x86/PCI" so it matches the previous
> convention.
Will do.
Thanks,
Tom
>
>>>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>
>>>> ---
>>>> arch/x86/pci/common.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
>>>> index a4fdfa7..0b06670 100644
>>>> --- a/arch/x86/pci/common.c
>>>> +++ b/arch/x86/pci/common.c
>>>> @@ -691,7 +691,7 @@ int pcibios_add_device(struct pci_dev *dev)
>>>>
>>>> pa_data = boot_params.hdr.setup_data;
>>>> while (pa_data) {
>>>> - data = ioremap(pa_data, sizeof(*rom));
>>>> + data = memremap(pa_data, sizeof(*rom), MEMREMAP_WB);
>>>
>>> I can't quite connect the dots here. ioremap() on x86 would do
>>> ioremap_nocache(). memremap(MEMREMAP_WB) would do arch_memremap_wb(),
>>> which is ioremap_cache(). Is making a cacheable mapping the important
>>> difference?
>>
>> The memremap(MEMREMAP_WB) will actually check to see if it can perform
>> a __va(pa_data) in try_ram_remap() and then fallback to the
>> arch_memremap_wb(). So it's actually the __va() vs the ioremap_cache()
>> that is the difference.
>>
>> Thanks,
>> Tom
>>
>>>
>>>> if (!data)
>>>> return -ENOMEM;
>>>>
>>>> @@ -710,7 +710,7 @@ int pcibios_add_device(struct pci_dev *dev)
>>>> }
>>>> }
>>>> pa_data = data->next;
>>>> - iounmap(data);
>>>> + memunmap(data);
>>>> }
>>>> set_dma_domain_ops(dev);
>>>> set_dev_domain_options(dev);
>>>>
--
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next prev parent reply other threads:[~2017-03-13 20:09 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 15:12 [RFC PATCH v2 00/32] x86: Secure Encrypted Virtualization (AMD) Brijesh Singh
2017-03-02 15:12 ` [RFC PATCH v2 01/32] x86: Add the Secure Encrypted Virtualization CPU feature Brijesh Singh
2017-03-03 16:59 ` Borislav Petkov
2017-03-03 21:01 ` Brijesh Singh
2017-03-04 10:11 ` Borislav Petkov
2017-03-06 18:11 ` Brijesh Singh
2017-03-06 20:54 ` Borislav Petkov
2017-03-02 15:12 ` [RFC PATCH v2 02/32] x86: Secure Encrypted Virtualization (SEV) support Brijesh Singh
2017-03-07 11:19 ` Borislav Petkov
2017-03-08 15:06 ` Borislav Petkov
2017-03-02 15:12 ` [RFC PATCH v2 03/32] KVM: SVM: prepare for new bit definition in nested_ctl Brijesh Singh
2017-03-02 15:12 ` [RFC PATCH v2 04/32] KVM: SVM: Add SEV feature definitions to KVM Brijesh Singh
2017-03-07 0:50 ` Borislav Petkov
2017-03-02 15:12 ` [RFC PATCH v2 05/32] x86: Use encrypted access of BOOT related data with SEV Brijesh Singh
2017-03-07 11:09 ` Borislav Petkov
2017-03-16 19:03 ` Tom Lendacky
2017-03-02 15:13 ` [RFC PATCH v2 06/32] x86/pci: Use memremap when walking setup data Brijesh Singh
2017-03-03 20:42 ` Bjorn Helgaas
2017-03-03 21:15 ` Tom Lendacky
2017-03-07 0:03 ` Bjorn Helgaas
2017-03-13 20:08 ` Tom Lendacky [this message]
2017-03-02 15:13 ` [RFC PATCH v2 07/32] x86/efi: Access EFI data as encrypted when SEV is active Brijesh Singh
2017-03-07 11:57 ` Borislav Petkov
2017-03-02 15:13 ` [RFC PATCH v2 08/32] x86: Use PAGE_KERNEL protection for ioremap of memory page Brijesh Singh
2017-03-07 14:59 ` Borislav Petkov
2017-03-16 20:04 ` Tom Lendacky
2017-03-17 14:32 ` Tom Lendacky
2017-03-17 14:55 ` Tom Lendacky
2017-03-02 15:13 ` [RFC PATCH v2 09/32] x86: Change early_ioremap to early_memremap for BOOT data Brijesh Singh
2017-03-08 8:46 ` Borislav Petkov
2017-03-02 15:14 ` [RFC PATCH v2 10/32] x86: DMA support for SEV memory encryption Brijesh Singh
2017-03-08 10:56 ` Borislav Petkov
2017-03-02 15:14 ` [RFC PATCH v2 11/32] x86: Unroll string I/O when SEV is active Brijesh Singh
2017-03-02 15:14 ` [RFC PATCH v2 12/32] x86: Add early boot support when running with SEV active Brijesh Singh
2017-03-09 14:07 ` Borislav Petkov
2017-03-09 16:13 ` Paolo Bonzini
2017-03-09 16:29 ` Borislav Petkov
2017-03-10 16:35 ` Brijesh Singh
2017-03-16 10:16 ` Borislav Petkov
2017-03-16 14:28 ` Tom Lendacky
2017-03-16 15:09 ` Borislav Petkov
2017-03-16 16:11 ` Tom Lendacky
2017-03-16 16:29 ` Borislav Petkov
2017-03-02 15:15 ` [RFC PATCH v2 13/32] KVM: SVM: Enable SEV by setting the SEV_ENABLE CPU feature Brijesh Singh
2017-03-09 19:29 ` Borislav Petkov
2017-03-02 15:15 ` [RFC PATCH v2 14/32] x86: mm: Provide support to use memblock when spliting large pages Brijesh Singh
2017-03-10 11:06 ` Borislav Petkov
2017-03-10 22:41 ` Brijesh Singh
2017-03-16 13:15 ` Paolo Bonzini
2017-03-16 18:28 ` Borislav Petkov
2017-03-16 22:25 ` Paolo Bonzini
2017-03-17 10:17 ` Borislav Petkov
2017-03-17 10:47 ` Paolo Bonzini
2017-03-17 10:56 ` Borislav Petkov
2017-03-17 11:03 ` Paolo Bonzini
2017-03-17 11:33 ` Borislav Petkov
2017-03-17 14:45 ` Paolo Bonzini
2017-03-18 16:37 ` Borislav Petkov
2017-04-06 14:05 ` Brijesh Singh
2017-04-06 17:25 ` Borislav Petkov
2017-04-06 18:37 ` Brijesh Singh
2017-04-07 11:33 ` Borislav Petkov
2017-04-07 14:50 ` Brijesh Singh
2017-03-16 12:28 ` Paolo Bonzini
2017-03-02 15:15 ` [RFC PATCH v2 15/32] x86: Add support for changing memory encryption attribute in early boot Brijesh Singh
2017-03-24 17:12 ` Borislav Petkov
2017-03-27 15:07 ` Brijesh Singh
2017-03-02 15:15 ` [RFC PATCH v2 16/32] x86: kvm: Provide support to create Guest and HV shared per-CPU variables Brijesh Singh
2017-03-16 11:06 ` Paolo Bonzini
2017-03-28 18:39 ` Borislav Petkov
2017-03-29 15:21 ` Paolo Bonzini
2017-03-29 15:32 ` Borislav Petkov
2017-03-02 15:15 ` [RFC PATCH v2 17/32] x86: kvmclock: Clear encryption attribute when SEV is active Brijesh Singh
2017-03-02 15:16 ` [RFC PATCH v2 18/32] kvm: svm: Use the hardware provided GPA instead of page walk Brijesh Singh
2017-03-29 15:14 ` Borislav Petkov
2017-03-29 17:08 ` Brijesh Singh
2017-03-02 15:16 ` [RFC PATCH v2 19/32] crypto: ccp: Introduce the AMD Secure Processor device Brijesh Singh
2017-03-02 17:39 ` Mark Rutland
2017-03-02 19:11 ` Brijesh Singh
2017-03-03 13:55 ` Andy Shevchenko
2017-03-02 15:16 ` [RFC PATCH v2 20/32] crypto: ccp: Add Platform Security Processor (PSP) interface support Brijesh Singh
2017-03-02 15:16 ` [RFC PATCH v2 21/32] crypto: ccp: Add Secure Encrypted Virtualization (SEV) " Brijesh Singh
2017-03-02 15:16 ` [RFC PATCH v2 22/32] kvm: svm: prepare to reserve asid for SEV guest Brijesh Singh
2017-03-02 15:17 ` [RFC PATCH v2 23/32] kvm: introduce KVM_MEMORY_ENCRYPT_OP ioctl Brijesh Singh
2017-03-16 10:25 ` Paolo Bonzini
2017-03-02 15:17 ` [RFC PATCH v2 24/32] kvm: x86: prepare for SEV guest management API support Brijesh Singh
2017-03-16 10:33 ` Paolo Bonzini
2017-03-02 15:17 ` [RFC PATCH v2 25/32] kvm: svm: Add support for SEV LAUNCH_START command Brijesh Singh
2017-03-02 15:17 ` [RFC PATCH v2 26/32] kvm: svm: Add support for SEV LAUNCH_UPDATE_DATA command Brijesh Singh
2017-03-16 10:48 ` Paolo Bonzini
2017-03-16 18:20 ` Brijesh Singh
2017-03-02 15:17 ` [RFC PATCH v2 27/32] kvm: svm: Add support for SEV LAUNCH_FINISH command Brijesh Singh
2017-03-02 15:18 ` [RFC PATCH v2 28/32] kvm: svm: Add support for SEV GUEST_STATUS command Brijesh Singh
2017-03-02 15:18 ` [RFC PATCH v2 29/32] kvm: svm: Add support for SEV DEBUG_DECRYPT command Brijesh Singh
2017-03-16 10:54 ` Paolo Bonzini
2017-03-16 18:41 ` Brijesh Singh
2017-03-17 11:09 ` Paolo Bonzini
2017-03-02 15:18 ` [RFC PATCH v2 30/32] kvm: svm: Add support for SEV DEBUG_ENCRYPT command Brijesh Singh
2017-03-16 11:03 ` Paolo Bonzini
2017-03-16 18:34 ` Brijesh Singh
2017-03-02 15:18 ` [RFC PATCH v2 31/32] kvm: svm: Add support for SEV LAUNCH_MEASURE command Brijesh Singh
2017-03-02 15:18 ` [RFC PATCH v2 32/32] x86: kvm: Pin the guest memory when SEV is active Brijesh Singh
2017-03-16 10:38 ` Paolo Bonzini
2017-03-16 18:17 ` Brijesh Singh
2017-03-03 20:33 ` [RFC PATCH v2 00/32] x86: Secure Encrypted Virtualization (AMD) Bjorn Helgaas
2017-03-03 20:51 ` Borislav Petkov
2017-03-03 21:15 ` Brijesh Singh
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