From: Ram Pai <linuxram@us.ibm.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
Michael Anderson <andmike@linux.ibm.com>,
Claudio Carvalho <cclaudio@linux.ibm.com>,
kvm-ppc@vger.kernel.org, Bharata B Rao <bharata@linux.ibm.com>,
linuxppc-dev@ozlabs.org,
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
Thiago Bauermann <bauermann@linux.ibm.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>
Subject: Re: Re: [PATCH v3 4/9] KVM: PPC: Ultravisor: Add generic ultravisor call handler
Date: Tue, 18 Jun 2019 08:25:35 -0700 [thread overview]
Message-ID: <20190618152535.GD10806@ram.ibm.com> (raw)
In-Reply-To: <20190618114701.GH7313@gate.crashing.org>
On Tue, Jun 18, 2019 at 06:47:01AM -0500, Segher Boessenkool wrote:
> Hi Paul,
>
> On Mon, Jun 17, 2019 at 12:06:32PM +1000, Paul Mackerras wrote:
> > The thing we need to consider is that when SMFCTRL[E] = 0, a ucall
> > instruction becomes a hcall (that is, sc 2 is executed as if it was
> > sc 1). In that case, the first argument to the ucall will be
> > interpreted as the hcall number. Mostly that will happen not to be a
> > valid hcall number, but sometimes it might unavoidably be a valid but
> > unintended hcall number.
>
> Shouldn't a caller of the ultravisor *know* that it is talking to the
> ultravisor in the first place? And not to the hypervisor.
It may or may not. But if it knows and still decides to make the ucall,
the hypervisor must gracefully handle it.
We can't control who makes a ucall. A normal process within the VM could
make a ucall too. Or a normal process running on top of the hypervisor
could make a ucall.
RP
next prev parent reply other threads:[~2019-06-18 15:28 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 17:36 [PATCH v3 0/9] kvmppc: Paravirtualize KVM to support ultravisor Claudio Carvalho
2019-06-06 17:36 ` [PATCH v3 1/9] KVM: PPC: Ultravisor: Add PPC_UV config option Claudio Carvalho
2019-06-07 20:11 ` Leonardo Bras
2019-06-10 12:18 ` Claudio Carvalho
2019-06-06 17:36 ` [PATCH v3 2/9] KVM: PPC: Ultravisor: Introduce the MSR_S bit Claudio Carvalho
2019-06-06 17:36 ` [PATCH v3 3/9] powerpc: Introduce FW_FEATURE_ULTRAVISOR Claudio Carvalho
2019-06-15 7:36 ` Paul Mackerras
2019-07-01 14:12 ` Claudio Carvalho
2019-06-06 17:36 ` [PATCH v3 4/9] KVM: PPC: Ultravisor: Add generic ultravisor call handler Claudio Carvalho
2019-06-15 7:37 ` Paul Mackerras
2019-06-17 2:06 ` Paul Mackerras
2019-06-17 23:51 ` Ram Pai
2019-06-18 11:47 ` Segher Boessenkool
2019-06-18 15:25 ` Ram Pai [this message]
2019-06-06 17:36 ` [PATCH v3 5/9] KVM: PPC: Ultravisor: Use UV_WRITE_PATE ucall to register a PATE Claudio Carvalho
2019-06-15 7:38 ` Paul Mackerras
2019-06-06 17:36 ` [PATCH v3 6/9] KVM: PPC: Ultravisor: Restrict flush of the partition tlb cache Claudio Carvalho
2019-06-06 19:39 ` Murilo Opsfelder Araújo
2019-06-06 21:55 ` Paul Mackerras
2019-06-06 17:36 ` [PATCH v3 7/9] KVM: PPC: Ultravisor: Restrict LDBAR access Claudio Carvalho
2019-06-07 4:48 ` Madhavan Srinivasan
2019-06-07 12:34 ` Claudio Carvalho
2019-06-15 7:43 ` Paul Mackerras
2019-06-16 1:10 ` Ram Pai
2019-06-06 17:36 ` [PATCH v3 8/9] KVM: PPC: Ultravisor: Enter a secure guest Claudio Carvalho
2019-06-15 7:45 ` Paul Mackerras
2019-06-06 17:36 ` [PATCH v3 9/9] KVM: PPC: Ultravisor: Check for MSR_S during hv_reset_msr Claudio Carvalho
2019-06-15 7:47 ` Paul Mackerras
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190618152535.GD10806@ram.ibm.com \
--to=linuxram@us.ibm.com \
--cc=andmike@linux.ibm.com \
--cc=bauermann@linux.ibm.com \
--cc=bharata@linux.ibm.com \
--cc=cclaudio@linux.ibm.com \
--cc=khandual@linux.vnet.ibm.com \
--cc=kvm-ppc@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=maddy@linux.vnet.ibm.com \
--cc=segher@kernel.crashing.org \
--cc=sukadev@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).