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Wed, 30 Mar 2022 12:26:17 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.13.95]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 30 Mar 2022 12:26:17 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, mimu@linux.ibm.com, nrb@linux.ibm.com Subject: [PATCH v9 11/18] s390/mm: KVM: pv: when tearing down, try to destroy protected pages Date: Wed, 30 Mar 2022 14:25:58 +0200 Message-Id: <20220330122605.247613-12-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220330122605.247613-1-imbrenda@linux.ibm.com> References: <20220330122605.247613-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: M1jaYmfTaYuZWq6-3vV-c_h_txxO076J X-Proofpoint-GUID: wW6xUb-XL1kddf_8poiLbf6Q4a6_U0Bn X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-30_03,2022-03-30_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 lowpriorityscore=0 mlxscore=0 adultscore=0 impostorscore=0 mlxlogscore=996 malwarescore=0 clxscore=1015 suspectscore=0 bulkscore=0 priorityscore=1501 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203300062 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org When ptep_get_and_clear_full is called for a mm teardown, we will now attempt to destroy the secure pages. This will be faster than export. In case it was not a teardown, or if for some reason the destroy page UVC failed, we try with an export page, like before. Signed-off-by: Claudio Imbrenda Acked-by: Janosch Frank --- arch/s390/include/asm/pgtable.h | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 23ca0d8e058a..72544a1b4a68 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1118,9 +1118,21 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, } else { res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID)); } - /* At this point the reference through the mapping is still present */ - if (mm_is_protected(mm) && pte_present(res)) - uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK); + /* Nothing to do */ + if (!mm_is_protected(mm) || !pte_present(res)) + return res; + /* + * At this point the reference through the mapping is still present. + * The notifier should have destroyed all protected vCPUs at this + * point, so the destroy should be successful. + */ + if (full && !uv_destroy_owned_page(pte_val(res) & PAGE_MASK)) + return res; + /* + * But if something went wrong and the pages could not be destroyed, + * the slower export is used as fallback instead. + */ + uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK); return res; }