Messages in this thread | | | Date | Mon, 10 Sep 2018 14:04:16 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v6 4/5] x86/kvm: use __decrypted attribute in shared variables |
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On Fri, Sep 07, 2018 at 12:57:29PM -0500, Brijesh Singh wrote: > Commit: 368a540e0232 (x86/kvmclock: Remove memblock dependency) > caused SEV guest regression.
When mentioning a commit in the commit message, put it on a separate line, like this:
"Commit
368a540e0232 (x86/kvmclock: Remove memblock dependency)
caused a SEV guest regression."
> When SEV is active, we map the shared
Use passive tone in your commit message: no "we", etc...
> variables (wall_clock and hv_clock_boot) with C=0 to ensure that both > the guest and the hypervisor are able to access the data. To map the > variables we use kernel_physical_mapping_init() to split the large pages,
"... to potentially split large pages used for that mapping... "
> but splitting large pages requires allocating a new PMD, which fails now > that kvmclock initialization is called early during boot.
"... before the memblock allocator is initialized."
> Recently we added a special .data..decrypted section to hold the shared > variables.
You don't really need that sentence.
> This section is mapped with C=0 early during boot. Use > __decrypted attribute to put the wall_clock and hv_clock_boot in > .data..decrypted section so that they are mapped with C=0.
"... so that they're mapped decrypted." Readers don't care about C=0 - they simply wanna know what C=0 represents, i.e., memory is not encrypted.
With that:
Reviewed-by: Borislav Petkov <bp@suse.de>
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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