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Re: SEV guest debugging support for Qemu
From: |
Paolo Bonzini |
Subject: |
Re: SEV guest debugging support for Qemu |
Date: |
Sat, 26 Sep 2020 02:02:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 |
On 26/09/20 01:48, Ashish Kalra wrote:
> Thanks for your input, i have one additional query with reference to this
> support :
>
> For all explicitly unecrypted guest memory regions such as S/W IOTLB bounce
> buffers,
> dma_decrypted() allocated regions and for guest regions marked as
> "__bss_decrypted",
> we need to ensure that DBG_DECRYPT API calls are bypassed for such
> regions and those regions are dumped as un-encrypted.
Yes those would be a bit different as they would be physical memory
accesses. Those currently go through address_space_read in memory_dump
(monitor/misc.c), and would have to use the MemoryDebugOps instead.
That is the place to hook into in order to read the KVM page encryption
bitmap (which is not per-CPU, so another MemoryDebugOps entry
get_phys_addr_attrs?); the MemTxAttrs can then be passed to the read
function in the MemoryDebugOps.
> This guest memory regions encryption status is found using KVM's page
> encryption bitmap
> support which is part of the page encryption bitmap hypercall interface of the
> KVM/QEMU SEV live migration patches.
>
> As this additional debug support is dependent on the KVM's page encryption
> bitmap
> support, are there any updates on KVM SEV live migration patches ?
Sorry about that, I've been busy with QEMU. I'll review them as soon as
possible.
Paolo
Re: SEV guest debugging support for Qemu, Paolo Bonzini, 2020/09/25