From: Thomas Huth <thuth@redhat.com>
To: "Janosch Frank" <frankja@linux.ibm.com>,
"Cédric Le Goater" <clg@kaod.org>,
qemu-s390x@nongnu.org
Cc: qemu-devel@nongnu.org, "Halil Pasic" <pasic@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@linux.ibm.com>,
"Claudio Imbrenda" <imbrenda@linux.ibm.com>,
"David Hildenbrand" <david@redhat.com>,
"Ilya Leoshkevich" <iii@linux.ibm.com>,
"Eric Farman" <farman@linux.ibm.com>,
"Sebastian Mitterle" <smitterl@redhat.com>,
"Cédric Le Goater" <clg@redhat.com>
Subject: Re: [PATCH v3 2/3] s390x/pv: Introduce a s390_pv_check() helper for runtime
Date: Tue, 17 Jan 2023 10:09:47 +0100 [thread overview]
Message-ID: <e87024f2-6ecf-1015-cc8c-604b17e139e2@redhat.com> (raw)
In-Reply-To: <a386bb49-72de-6edc-9873-70ec59e475ab@linux.ibm.com>
On 17/01/2023 09.40, Janosch Frank wrote:
> On 1/16/23 18:46, Cédric Le Goater wrote:
>> From: Cédric Le Goater <clg@redhat.com>
>>
>> If a secure kernel is started in a non-protected VM, the OS will hang
>> during boot without giving a proper error message to the user.
>
> Didn't we establish that you were missing the IOMMU flag so this statement
> isn't correct anymore?
>
>
> I haven't yet fully ingested my coffee, but from what I understand you would
> block a switch into PV mode if cgs is not set. Which would mean that PV KVM
> unit tests wouldn't start anymore as well as any VMs that have the unpack
> feature but not cgs.
>
> And that's not something that we want.
>
> You can start a PV VM without cgs if unpack is in the CPU model. The ONLY
> requirement that we should fail on is unpack.
So would it make sense to check for S390_FEAT_UNPACK (or something else?)
here, or should the patch completely be dropped instead?
Thomas
next prev parent reply other threads:[~2023-01-17 9:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-16 17:46 [PATCH v3 0/3]s390x/pv: Improve error reporting of protected VMs Cédric Le Goater
2023-01-16 17:46 ` [PATCH v3 1/3] s390x/pv: Implement a CGS check helper Cédric Le Goater
2023-01-16 17:46 ` [PATCH v3 2/3] s390x/pv: Introduce a s390_pv_check() helper for runtime Cédric Le Goater
2023-01-17 7:59 ` Thomas Huth
2023-01-17 8:40 ` Janosch Frank
2023-01-17 8:56 ` Cédric Le Goater
2023-01-17 9:09 ` Thomas Huth [this message]
2023-01-17 9:28 ` Janosch Frank
2023-01-16 17:46 ` [PATCH v3 3/3] s390x/pv: Move check on hugepage under s390_pv_guest_check() Cédric Le Goater
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