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Wed, 4 Feb 2026 15:23:56 +0000 (GMT) Date: Wed, 4 Feb 2026 16:23:54 +0100 From: Heiko Carstens To: Claudio Imbrenda Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, nsg@linux.ibm.com, nrb@linux.ibm.com, seiden@linux.ibm.com, gra@linux.ibm.com, schlameuss@linux.ibm.com, svens@linux.ibm.com, agordeev@linux.ibm.com, gor@linux.ibm.com, david@kernel.org, gerald.schaefer@linux.ibm.com Subject: Re: [PATCH v7 00/29] KVM: s390: gmap rewrite, the real deal Message-ID: <20260204152354.6906B2f-hca@linux.ibm.com> References: <20260204150259.60425-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260204150259.60425-1-imbrenda@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjA0MDExNyBTYWx0ZWRfX1J8Lp1NuzHDb in3VtW8ZIye0Vn0FG2sL2ekA0ZT6rKjF3mq8HXmW1Dsp/hpMsKV56C+i0lga1ncP7Xrq9wO+EjI m+cwAVBBbCeHipsF8/G5osb4dkO+PSHQl03lfNyhGMj9c/Ieti0e1alxoH7V+NI1YBoYfoPtwnh vOWF/ijw3E753wpKj8f5RugrVh2a6/I7BjyBpe//AilnDggwEQBLXFBdYRj8OG50LM4yz56OK1e Dp5/psvqfmqB2VZB/8bFtu4lfGBZ6oaNZ+QgNEuQdPGaW2DD9YjctzLE2e+C76hJAZwQIUZG9cA 5j1RjTOXwYaoEi+C8ryK08sNepjlUvRzFlqah1Ybx7A8XU/GLG0XhmipIC93OSiyHBKWnpzlL48 AZjPIeoZTaQi/oJtVAQJMl3o2kx0M4Fi8P6AslDlozg5ppRdh6KmupGWN4oAdzrfC3/d2F9bH3i 65GaJ7hsXYHMghVP5Xw== X-Proofpoint-GUID: lJWw9RLpYBM_GQ6KM8oQ2GX-0BMkzTVl X-Proofpoint-ORIG-GUID: lJWw9RLpYBM_GQ6KM8oQ2GX-0BMkzTVl X-Authority-Analysis: v=2.4 cv=LesxKzfi c=1 sm=1 tr=0 ts=69836492 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=kj9zAlcOel0A:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=zp8rA2SfgbRMV71b97gA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-04_04,2026-02-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 suspectscore=0 priorityscore=1501 phishscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2602040117 On Wed, Feb 04, 2026 at 04:02:29PM +0100, Claudio Imbrenda wrote: > This series is the last big series of the gmap rewrite. It introduces > the new code and actually uses it. The old code is then removed. > > KVM on s390 will now use the mmu_notifier, like most other > architectures. The gmap address space is now completely separate from > userspace; no level of the page tables is shared between guest mapping > and userspace. > > One of the biggest advantages is that the page size of userspace is > completely independent of the page size used by the guest. Userspace > can mix normal pages, THPs, hugetlbfs, and more. > > It's now possible to have nested guests and guests with huge pages > running on the same host. In fact, it's possible to have a nested > guest on a guest with huge pages. Transparent hugepages are also > possible. FWIW, for everything that touches code which is not only KVM: Acked-by: Heiko Carstens