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From: Julien Grall <julien.grall@arm.com>
To: Shannon Zhao <shannon.zhao@linaro.org>,
	Shannon Zhao <zhaoshenglong@huawei.com>,
	xen-devel@lists.xen.org
Cc: stefano.stabellini@citrix.com, peter.huangpeng@huawei.com
Subject: Re: [PATCH v6 13/22] arm/acpi: Map the new created EFI and ACPI tables to Dom0
Date: Thu, 24 Mar 2016 15:35:48 +0000	[thread overview]
Message-ID: <56F40954.8060602@arm.com> (raw)
In-Reply-To: <56F400E0.7030501@linaro.org>

Hi Shannon,

On 24/03/16 14:59, Shannon Zhao wrote:
> On 2016年03月23日 00:16, Julien Grall wrote:
>> On 22/03/16 13:18, Shannon Zhao wrote:
>>> On 2016年03月22日 08:42, Julien Grall wrote:
>>>> On 17/03/2016 09:40, Shannon Zhao wrote:
>>>>> From: Shannon Zhao <shannon.zhao@linaro.org>
>>>>>
>>>>> Map the UEFI and ACPI tables which we created to non-RAM space in Dom0.
>>>>>
>>>>> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
>>>>> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>>>>> ---
>>>>>     xen/arch/arm/domain_build.c | 15 +++++++++++++++
>>>>>     1 file changed, 15 insertions(+)
>>>>>
>>>>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
>>>>> index 008fc76..e036887 100644
>>>>> --- a/xen/arch/arm/domain_build.c
>>>>> +++ b/xen/arch/arm/domain_build.c
>>>>> @@ -1691,6 +1691,21 @@ static int prepare_acpi(struct domain *d,
>>>>> struct kernel_info *kinfo)
>>>>>         acpi_create_efi_mmap_table(d->arch.efi_acpi_gpa,
>>>>> d->arch.efi_acpi_len,
>>>>>                                    d->arch.efi_acpi_table, &kinfo->mem,
>>>>> tbl_add);
>>>>>
>>>>> +    /* Map the EFI and ACPI tables to Dom0 */
>>>>> +    rc = map_regions_rw(d,
>>>>> +                        paddr_to_pfn(d->arch.efi_acpi_gpa),
>>>>> +                        PFN_UP(d->arch.efi_acpi_len),
>>>>> +
>>>>> paddr_to_pfn(virt_to_maddr(d->arch.efi_acpi_table)));
>>>>
>>>> The ACPI/EFI tables could potentially have data in the cache but are not
>>>> written into the memory (because Xen is mapping the RAM with caching
>>>> enabled). However, DOM0 may decide to map it with cache disabled.
>>>> Therefore it would be possible for the domain to see wrong data.
>>>>
>>>> So I think you need to clean the cache for this region.
>>> Oh, that would be good. Is there any existing function I can use?
>>
>> You could reuse p2m_cache_flush. However this function will only flush
>> cache for p2m_ram_* entries.
>>
>> I think the best way would be to extend the CACHEFLUSH operations and
>> maybe p2m_cache_flush (?).
> So it needs to extend the CACHEFLUSH case to handle the p2m_mmio_direct
> entry, right?

Hmmm thinking a bit more about this solution. It would allow a domain to 
flush device memory region. And we don't want that.

There is actually a simpler solution, you can directly call 
clean_and_invalidate_dcache_va_range on your buffer. I.e

clean_and_invalidate_dcache_va_range(d->arch.efi_acpi_table, 
d->arch.efi_acpi_len);

>
> BTW, does the case you said exist? Before xen switches to Dom0, will it
> invalid the cache?

Yes, we had some issue in the past with the kernel, device tree, and 
initramfs passed to a domain. The domains boot with cache disabled, the 
domains will retrieve garbage if the data didn't reach the RAM.

Currently, Xen only flushes some part of the cache associated to the 
data copied in the guest memory (for instance see 
raw_copy_to_guest_flush_dcache).

Regards,

-- 
Julien Grall

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  reply	other threads:[~2016-03-24 15:35 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-17  9:40 [PATCH v6 00/22] Prepare UEFI and ACPI tables for Dom0 on ARM64 Shannon Zhao
2016-03-17  9:40 ` [PATCH v6 01/22] arm/acpi: Estimate memory required for acpi/efi tables Shannon Zhao
2016-03-18 18:44   ` Julien Grall
2016-03-21 13:01     ` Jan Beulich
2016-03-22 13:01     ` Shannon Zhao
2016-03-22  0:28   ` Julien Grall
2016-03-24 12:36   ` Stefano Stabellini
2016-03-17  9:40 ` [PATCH v6 02/22] arm/acpi: Add a helper function to get the acpi table offset Shannon Zhao
2016-03-21 12:16   ` Julien Grall
2016-03-24 12:32   ` Stefano Stabellini
2016-03-17  9:40 ` [PATCH v6 03/22] arm/acpi: Prepare FADT table for Dom0 Shannon Zhao
2016-03-21 12:25   ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 04/22] arm/gic: Add a new callback for creating MADT " Shannon Zhao
2016-03-21 15:18   ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 05/22] arm/acpi: Prepare " Shannon Zhao
2016-03-21 15:26   ` Julien Grall
2016-03-21 15:51     ` Jan Beulich
2016-03-17  9:40 ` [PATCH v6 06/22] arm/acpi: Prepare STAO " Shannon Zhao
2016-03-21 15:31   ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 07/22] arm/acpi: Prepare XSDT " Shannon Zhao
2016-03-21 15:43   ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 08/22] arm/acpi: Prepare RSDP " Shannon Zhao
2016-03-21 15:47   ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 09/22] arm/p2m: Add helper functions to map memory regions Shannon Zhao
2016-03-21 15:52   ` Julien Grall
2016-03-22 13:05     ` Shannon Zhao
2016-03-22 15:59       ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 10/22] arm/acpi: Map all other tables for Dom0 Shannon Zhao
2016-03-21 15:57   ` Julien Grall
2016-03-17  9:40 ` [PATCH v6 11/22] arm/acpi: Prepare EFI system table " Shannon Zhao
2016-03-21 16:10   ` Julien Grall
2016-03-22 13:06     ` Shannon Zhao
2016-03-22 13:24       ` Jan Beulich
2016-03-17  9:40 ` [PATCH v6 12/22] arm/acpi: Prepare EFI memory descriptor " Shannon Zhao
2016-03-21 16:51   ` Julien Grall
2016-03-22 13:16     ` Shannon Zhao
2016-03-22 16:04       ` Julien Grall
2016-03-24 15:06         ` Shannon Zhao
2016-03-24 15:23           ` Julien Grall
2016-03-24 12:39   ` Stefano Stabellini
2016-03-17  9:40 ` [PATCH v6 13/22] arm/acpi: Map the new created EFI and ACPI tables to Dom0 Shannon Zhao
2016-03-22  0:42   ` Julien Grall
2016-03-22 13:18     ` Shannon Zhao
2016-03-22 16:16       ` Julien Grall
2016-03-24 14:59         ` Shannon Zhao
2016-03-24 15:35           ` Julien Grall [this message]
2016-03-17  9:41 ` [PATCH v6 14/22] arm/acpi: Create min DT stub for Dom0 Shannon Zhao
2016-03-22  1:07   ` Julien Grall
2016-03-22 13:23     ` Shannon Zhao
2016-03-17  9:41 ` [PATCH v6 15/22] arm/acpi: Permit access all Xen unused SPIs " Shannon Zhao
2016-03-22 18:18   ` Julien Grall
2016-03-24 15:01     ` Shannon Zhao
2016-03-24 15:37       ` Julien Grall
2016-03-25  7:13         ` Shannon Zhao
2016-03-17  9:41 ` [PATCH v6 16/22] arm/acpi: Configure SPI interrupt type and route to Dom0 dynamically Shannon Zhao
2016-03-22 19:17   ` Julien Grall
2016-03-24 12:41   ` Stefano Stabellini
2016-03-17  9:41 ` [PATCH v6 17/22] arm/gic: Add a new callback to deny Dom0 access to GIC regions Shannon Zhao
2016-03-22 19:33   ` Julien Grall
2016-03-24 12:45     ` Stefano Stabellini
2016-03-24 15:03       ` Shannon Zhao
2016-03-24 15:39         ` Julien Grall
2016-03-17  9:41 ` [PATCH v6 18/22] arm/acpi: Permit MMIO access of Xen unused devices for Dom0 Shannon Zhao
2016-03-23 11:50   ` Julien Grall
2016-03-17  9:41 ` [PATCH v6 19/22] hvm/params: Add a new delivery type for event-channel in HVM_PARAM_CALLBACK_IRQ Shannon Zhao
2016-03-17 10:42   ` Jan Beulich
2016-03-17 11:04     ` Shannon Zhao
2016-03-17 11:29       ` Jan Beulich
2016-03-17 11:56         ` Shannon Zhao
2016-03-17 12:42           ` Jan Beulich
2016-03-17  9:41 ` [PATCH v6 20/22] xen/acpi: Fix event-channel interrupt when booting with ACPI Shannon Zhao
2016-03-23 12:15   ` Julien Grall
2016-03-17  9:41 ` [PATCH v6 21/22] xen/arm: Add a hypercall for device mmio mapping Shannon Zhao
2016-03-17  9:41 ` [PATCH v6 22/22] xen/arm64: Add ACPI support Shannon Zhao
2016-03-17 10:52   ` Jan Beulich
2016-03-17 11:03     ` Shannon Zhao
2016-03-17 11:31       ` Jan Beulich
2016-03-17 13:10         ` Shannon Zhao
2016-03-17 13:24           ` Jan Beulich

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