From: David Hildenbrand <david@redhat.com>
To: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org, frankja@linux.ibm.com,
borntraeger@de.ibm.com, nrb@linux.ibm.com, seiden@linux.ibm.com,
nsg@linux.ibm.com, schlameuss@linux.ibm.com, hca@linux.ibm.com
Subject: Re: [PATCH v2 1/1] KVM: s390: pv: fix race when making a page secure
Date: Wed, 26 Feb 2025 18:01:04 +0100 [thread overview]
Message-ID: <bab79dbd-64cc-4a58-aba9-bc5fd4d6beca@redhat.com> (raw)
In-Reply-To: <20250226175833.16a7a970@p-imbrenda>
On 26.02.25 17:58, Claudio Imbrenda wrote:
> On Wed, 26 Feb 2025 16:05:11 +0100
> David Hildenbrand <david@redhat.com> wrote:
>
>>> +int make_hva_secure(struct mm_struct *mm, unsigned long hva, struct uv_cb_header *uvcb)
>>> +{
>>> + struct folio *folio;
>>> + spinlock_t *ptelock;
>>> + pte_t *ptep;
>>> + int rc;
>>> +
>>> + ptep = get_locked_valid_pte(mm, hva, &ptelock);
>>> + if (!ptep)
>>> + return -ENXIO;
>>
>> You very likely need a pte_write() check we had there before, as you
>> might effectively modify page content by clearing the page.
>
> it's not really needed, but it doesn't hurt either, I'll add a check
Can you elaborate why it is not needed? Would the HW enforce that
writability check already?
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-02-26 17:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-26 12:37 [PATCH v2 0/1] KVM: s390: fix a newly introduced bug Claudio Imbrenda
2025-02-26 12:37 ` [PATCH v2 1/1] KVM: s390: pv: fix race when making a page secure Claudio Imbrenda
2025-02-26 15:05 ` David Hildenbrand
2025-02-26 16:58 ` Claudio Imbrenda
2025-02-26 17:01 ` David Hildenbrand [this message]
2025-02-26 17:26 ` Claudio Imbrenda
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