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Mon, 17 May 2021 20:07:32 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5514052059; Mon, 17 May 2021 20:08:00 +0000 (GMT) Received: from ibm-vm.ibmuc.com (unknown [9.145.14.34]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id E7A4752052; Mon, 17 May 2021 20:07:59 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: cohuck@redhat.com, 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 Subject: [PATCH v1 02/11] KVM: s390: pv: properly handle page flags for protected guests Date: Mon, 17 May 2021 22:07:49 +0200 Message-Id: <20210517200758.22593-3-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517200758.22593-1-imbrenda@linux.ibm.com> References: <20210517200758.22593-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: fWYbEYfXvR8nfsM6NgHZt-XfZPlA1Rk1 X-Proofpoint-ORIG-GUID: Gyp-WKOCVG5NN0DWTobXYkTHTeFzLWq4 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-05-17_08:2021-05-17,2021-05-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 phishscore=0 mlxlogscore=890 clxscore=1015 spamscore=0 lowpriorityscore=0 suspectscore=0 mlxscore=0 bulkscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105170140 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Introduce variants of the convert and destroy page functions that also clear the PG_arch_1 bit used to mark them as secure pages. These new functions can only be called on pages for which a reference is already being held. Signed-off-by: Claudio Imbrenda --- arch/s390/include/asm/pgtable.h | 9 ++++++--- arch/s390/include/asm/uv.h | 10 ++++++++-- arch/s390/kernel/uv.c | 34 ++++++++++++++++++++++++++++++++- arch/s390/mm/gmap.c | 4 +++- 4 files changed, 50 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 29c7ecd5ad1d..141a8aaacd6d 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1062,8 +1062,9 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, pte_t res; 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_from_secure(pte_val(res) & PAGE_MASK); + uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK); return res; } @@ -1079,8 +1080,9 @@ static inline pte_t ptep_clear_flush(struct vm_area_struct *vma, pte_t res; res = ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID)); + /* At this point the reference through the mapping is still present */ if (mm_is_protected(vma->vm_mm) && pte_present(res)) - uv_convert_from_secure(pte_val(res) & PAGE_MASK); + uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK); return res; } @@ -1104,8 +1106,9 @@ 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_from_secure(pte_val(res) & PAGE_MASK); + uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK); return res; } diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index 7b98d4caee77..9aa621e84745 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -345,8 +345,9 @@ static inline int is_prot_virt_host(void) } int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb); -int uv_destroy_page(unsigned long paddr); +int uv_destroy_owned_page(unsigned long paddr); int uv_convert_from_secure(unsigned long paddr); +int uv_convert_owned_from_secure(unsigned long paddr); int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr); void setup_uv(void); @@ -356,7 +357,7 @@ void adjust_to_uv_max(unsigned long *vmax); static inline void setup_uv(void) {} static inline void adjust_to_uv_max(unsigned long *vmax) {} -static inline int uv_destroy_page(unsigned long paddr) +static inline int uv_destroy_owned_page(unsigned long paddr) { return 0; } @@ -365,6 +366,11 @@ static inline int uv_convert_from_secure(unsigned long paddr) { return 0; } + +static inline int uv_convert_owned_from_secure(unsigned long paddr) +{ + return 0; +} #endif #if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) || IS_ENABLED(CONFIG_KVM) diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index b2d2ad153067..3d94760c0371 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -121,7 +121,7 @@ static int uv_pin_shared(unsigned long paddr) * * @paddr: Absolute host address of page to be destroyed */ -int uv_destroy_page(unsigned long paddr) +static int uv_destroy_page(unsigned long paddr) { struct uv_cb_cfs uvcb = { .header.cmd = UVC_CMD_DESTR_SEC_STOR, @@ -141,6 +141,22 @@ int uv_destroy_page(unsigned long paddr) return 0; } +/* + * The caller must already hold a reference to the page + */ +int uv_destroy_owned_page(unsigned long paddr) +{ + struct page *page = phys_to_page(paddr); + int rc; + + get_page(page); + rc = uv_destroy_page(paddr); + if (!rc) + clear_bit(PG_arch_1, &page->flags); + put_page(page); + return rc; +} + /* * Requests the Ultravisor to encrypt a guest page and make it * accessible to the host for paging (export). @@ -160,6 +176,22 @@ int uv_convert_from_secure(unsigned long paddr) return 0; } +/* + * The caller must already hold a reference to the page + */ +int uv_convert_owned_from_secure(unsigned long paddr) +{ + struct page *page = phys_to_page(paddr); + int rc; + + get_page(page); + rc = uv_convert_from_secure(paddr); + if (!rc) + clear_bit(PG_arch_1, &page->flags); + put_page(page); + return rc; +} + /* * Calculate the expected ref_count for a page that would otherwise have no * further pins. This was cribbed from similar functions in other places in diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 9bb2c7512cd5..de679facc720 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2678,8 +2678,10 @@ static int __s390_reset_acc(pte_t *ptep, unsigned long addr, { pte_t pte = READ_ONCE(*ptep); + /* There is a reference through the mapping */ if (pte_present(pte)) - WARN_ON_ONCE(uv_destroy_page(pte_val(pte) & PAGE_MASK)); + WARN_ON_ONCE(uv_destroy_owned_page(pte_val(pte) & PAGE_MASK)); + return 0; }