From: Bharata B Rao <bharata@linux.ibm.com>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: linuxram@us.ibm.com, cclaudio@linux.ibm.com,
kvm-ppc@vger.kernel.org, linux-mm@kvack.org, jglisse@redhat.com,
aneesh.kumar@linux.vnet.ibm.com, paulus@au1.ibm.com,
sukadev@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org,
hch@lst.de
Subject: Re: [PATCH v10 4/8] KVM: PPC: Radix changes for secure guest
Date: Wed, 6 Nov 2019 14:06:44 +0530 [thread overview]
Message-ID: <20191106083644.GE21634@in.ibm.com> (raw)
In-Reply-To: <20191106055823.GE12069@oak.ozlabs.ibm.com>
On Wed, Nov 06, 2019 at 04:58:23PM +1100, Paul Mackerras wrote:
> On Mon, Nov 04, 2019 at 09:47:56AM +0530, Bharata B Rao wrote:
> > - After the guest becomes secure, when we handle a page fault of a page
> > belonging to SVM in HV, send that page to UV via UV_PAGE_IN.
> > - Whenever a page is unmapped on the HV side, inform UV via UV_PAGE_INVAL.
> > - Ensure all those routines that walk the secondary page tables of
> > the guest don't do so in case of secure VM. For secure guest, the
> > active secondary page tables are in secure memory and the secondary
> > page tables in HV are freed when guest becomes secure.
>
> Why do we free the page tables? Just to save a little memory? It
> feels like it would make things more fragile.
I guess we could just leave the page tables around and they would get
populated again if and when the guest is reset (i,e., when it goes back
to non-secure mode)
However it appeared cleaner to cleanup the page tables given that aren't
in user any longer.
>
> Also, I don't see where the freeing gets done in this patch.
There isn't a very good reason for freeing code to be not part of this patch.
I just put that in reset patch (6/8) where there is code for reinitializing
page tables again.
Regards,
Bharata.
next prev parent reply other threads:[~2019-11-06 8:39 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 4:17 [PATCH v10 0/8] KVM: PPC: Driver to manage pages of secure guest Bharata B Rao
2019-11-04 4:17 ` [PATCH v10 1/8] mm: ksm: Export ksm_madvise() Bharata B Rao
2019-11-06 4:33 ` Paul Mackerras
2019-11-06 6:45 ` Bharata B Rao
2019-11-07 5:45 ` Paul Mackerras
2019-11-15 14:10 ` Bharata B Rao
2019-11-04 4:17 ` [PATCH v10 2/8] KVM: PPC: Support for running secure guests Bharata B Rao
2019-11-06 4:34 ` Paul Mackerras
2019-11-04 4:17 ` [PATCH v10 3/8] KVM: PPC: Shared pages support for " Bharata B Rao
2019-11-06 4:52 ` Paul Mackerras
2019-11-06 8:22 ` Bharata B Rao
2019-11-06 8:29 ` Bharata B Rao
2019-11-04 4:17 ` [PATCH v10 4/8] KVM: PPC: Radix changes for secure guest Bharata B Rao
2019-11-06 5:58 ` Paul Mackerras
2019-11-06 8:36 ` Bharata B Rao [this message]
2019-11-04 4:17 ` [PATCH v10 5/8] KVM: PPC: Handle memory plug/unplug to secure VM Bharata B Rao
2019-11-11 4:25 ` Paul Mackerras
2019-11-04 4:17 ` [PATCH v10 6/8] KVM: PPC: Support reset of secure guest Bharata B Rao
2019-11-11 5:28 ` Paul Mackerras
2019-11-11 6:55 ` Bharata B Rao
2019-11-12 5:34 ` Paul Mackerras
2019-11-13 15:29 ` Bharata B Rao
2019-11-14 5:07 ` Paul Mackerras
2019-11-04 4:17 ` [PATCH v10 7/8] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Bharata B Rao
2019-11-11 4:19 ` Paul Mackerras
2019-11-12 1:01 ` Ram Pai
2019-11-12 5:38 ` Paul Mackerras
2019-11-12 7:52 ` Ram Pai
2019-11-12 11:32 ` Paul Mackerras
2019-11-12 14:45 ` Ram Pai
2019-11-13 0:14 ` Paul Mackerras
2019-11-13 6:32 ` Ram Pai
2019-11-13 21:18 ` Paul Mackerras
2019-11-13 21:50 ` Ram Pai
2019-11-14 5:08 ` Paul Mackerras
2019-11-14 7:02 ` Ram Pai
2019-11-04 4:18 ` [PATCH v10 8/8] KVM: PPC: Ultravisor: Add PPC_UV config option Bharata B Rao
2019-11-06 4:30 ` [PATCH v10 0/8] KVM: PPC: Driver to manage pages of secure guest Paul Mackerras
2019-11-06 6:20 ` Bharata B Rao
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