Messages in this thread | | | Subject | Re: [PATCH v2 00/25] KVM SGX virtualization support | From | Kai Huang <> | Date | Thu, 11 Mar 2021 09:44:07 +1300 |
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On Wed, 2021-03-10 at 20:01 +0200, Jarkko Sakkinen wrote: > On Tue, Mar 09, 2021 at 10:30:37AM +0100, Borislav Petkov wrote: > > On Tue, Mar 09, 2021 at 02:38:49PM +1300, Kai Huang wrote: > > > This series adds KVM SGX virtualization support. The first 14 patches starting > > > with x86/sgx or x86/cpu.. are necessary changes to x86 and SGX core/driver to > > > support KVM SGX virtualization, while the rest are patches to KVM subsystem. > > > > Ok, I guess I'll queue 1-14 once Sean doesn't find anything > > objectionable then give Paolo an immutable commit to base the KVM stuff > > ontop. > > > > Unless folks have better suggestions, ofc. > > I'm otherwise cool with that, except patch #2. > > It's based on this series: > > https://lore.kernel.org/linux-sgx/20210113233541.17669-1-jarkko@kernel.org/ > > It's not reasonable to create driver specific wrapper for > sgx_free_epc_page() because there is exactly *2* call sites of the function > in the driver. The driver contains 10 call sites (11 after my NUMA patches > have been applied) of sgx_free_epc_page() in total. > > Instead, it is better to add explicit EREMOVE to those call sites. > > The wrapper only trashes the codebase. I'm not happy with it, given all the > trouble to make it clean and sound.
However, your change has side effort: it always put page back into free pool, even EREMOVE fails. To make your change w/o having any functional change, it has to be:
if(!sgx_reset_epc_page()) sgx_free_epc_page();
And for this, Dave raised one concern we should add a WARN() to let user know EPC page is leaked, and reboot is requied to get them back.
However with sgx_reset_epc_page(), there's no place to add such WARN(), and implementing original sgx_free_epc_page() as sgx_encl_free_epc_page() looks very reasonable to me:
https://www.spinics.net/lists/linux-sgx/msg04631.html
Hi Dave,
What is your comment here?
> > > Thx. > > > > -- > > Regards/Gruss, > > Boris. > > > > https://people.kernel.org/tglx/notes-about-netiquette > > > /Jarkko
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