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Fri, 07 Feb 2020 11:40:02 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 017Be0hC48496928 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Feb 2020 11:40:01 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C8E07AC05B; Fri, 7 Feb 2020 11:40:00 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A64AAAC065; Fri, 7 Feb 2020 11:40:00 +0000 (GMT) Received: from localhost.localdomain (unknown [9.114.17.106]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 7 Feb 2020 11:40:00 +0000 (GMT) From: Christian Borntraeger To: Christian Borntraeger , Janosch Frank Cc: KVM , Cornelia Huck , David Hildenbrand , Thomas Huth , Ulrich Weigand , Claudio Imbrenda , Andrea Arcangeli , linux-s390 , Michael Mueller , Vasily Gorbik , linux-mm@kvack.org, Andrew Morton Subject: [PATCH 05/35] s390/mm: provide memory management functions for protected KVM guests Date: Fri, 7 Feb 2020 06:39:28 -0500 Message-Id: <20200207113958.7320-6-borntraeger@de.ibm.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20200207113958.7320-1-borntraeger@de.ibm.com> References: <20200207113958.7320-1-borntraeger@de.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-07_01:2020-02-07,2020-02-06 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 mlxlogscore=999 impostorscore=0 malwarescore=0 suspectscore=2 phishscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 spamscore=0 clxscore=1015 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002070089 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Claudio Imbrenda This provides the basic ultravisor calls and page table handling to cope with secure guests: - provide arch_make_page_accessible - make pages accessible after unmapping of secure guests - provide the ultravisor commands convert to/from secure - provide the ultravisor commands pin/unpin shared - provide callbacks to make pages secure (inacccessible) - we check for the expected pin count to only make pages secure if the host is not accessing them - we fence hugetlbfs for secure pages Co-developed-by: Ulrich Weigand Signed-off-by: Ulrich Weigand Signed-off-by: Claudio Imbrenda [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/gmap.h | 2 + arch/s390/include/asm/mmu.h | 2 + arch/s390/include/asm/mmu_context.h | 1 + arch/s390/include/asm/page.h | 5 + arch/s390/include/asm/pgtable.h | 34 +++++- arch/s390/include/asm/uv.h | 52 +++++++++ arch/s390/kernel/uv.c | 172 ++++++++++++++++++++++++++++ 7 files changed, 263 insertions(+), 5 deletions(-) diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index 37f96b6f0e61..e2d2f48c5c7c 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -9,6 +9,7 @@ #ifndef _ASM_S390_GMAP_H #define _ASM_S390_GMAP_H +#include #include /* Generic bits for GMAP notification on DAT table entry changes. */ @@ -61,6 +62,7 @@ struct gmap { spinlock_t shadow_lock; struct gmap *parent; unsigned long orig_asce; + unsigned long guest_handle; int edat_level; bool removed; bool initialized; diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h index bcfb6371086f..e21b618ad432 100644 --- a/arch/s390/include/asm/mmu.h +++ b/arch/s390/include/asm/mmu.h @@ -16,6 +16,8 @@ typedef struct { unsigned long asce; unsigned long asce_limit; unsigned long vdso_base; + /* The mmu context belongs to a secure guest. */ + atomic_t is_protected; /* * The following bitfields need a down_write on the mm * semaphore when they are written to. As they are only diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h index 8d04e6f3f796..afa836014076 100644 --- a/arch/s390/include/asm/mmu_context.h +++ b/arch/s390/include/asm/mmu_context.h @@ -23,6 +23,7 @@ static inline int init_new_context(struct task_struct *tsk, INIT_LIST_HEAD(&mm->context.gmap_list); cpumask_clear(&mm->context.cpu_attach_mask); atomic_set(&mm->context.flush_count, 0); + atomic_set(&mm->context.is_protected, 0); mm->context.gmap_asce = 0; mm->context.flush_mm = 0; mm->context.compat_mm = test_thread_flag(TIF_31BIT); diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h index a4d38092530a..05ea3e42a041 100644 --- a/arch/s390/include/asm/page.h +++ b/arch/s390/include/asm/page.h @@ -151,6 +151,11 @@ static inline int devmem_is_allowed(unsigned long pfn) #define HAVE_ARCH_FREE_PAGE #define HAVE_ARCH_ALLOC_PAGE +#if IS_ENABLED(CONFIG_PGSTE) +int arch_make_page_accessible(struct page *page); +#define HAVE_ARCH_MAKE_PAGE_ACCESSIBLE +#endif + #endif /* !__ASSEMBLY__ */ #define __PAGE_OFFSET 0x0UL diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 7b03037a8475..dbd1453e6924 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -19,6 +19,7 @@ #include #include #include +#include extern pgd_t swapper_pg_dir[]; extern void paging_init(void); @@ -520,6 +521,15 @@ static inline int mm_has_pgste(struct mm_struct *mm) return 0; } +static inline int mm_is_protected(struct mm_struct *mm) +{ +#ifdef CONFIG_PGSTE + if (unlikely(atomic_read(&mm->context.is_protected))) + return 1; +#endif + return 0; +} + static inline int mm_alloc_pgste(struct mm_struct *mm) { #ifdef CONFIG_PGSTE @@ -1059,7 +1069,12 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma, static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - return ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID)); + pte_t res; + + res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID)); + if (mm_is_protected(mm) && pte_present(res)) + uv_convert_from_secure(pte_val(res) & PAGE_MASK); + return res; } #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION @@ -1071,7 +1086,12 @@ void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long, static inline pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { - return ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID)); + pte_t res; + + res = ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID)); + if (mm_is_protected(vma->vm_mm) && pte_present(res)) + uv_convert_from_secure(pte_val(res) & PAGE_MASK); + return res; } /* @@ -1086,12 +1106,16 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full) { + pte_t res; if (full) { - pte_t pte = *ptep; + res = *ptep; *ptep = __pte(_PAGE_INVALID); - return pte; + } else { + res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID)); } - return ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID)); + if (mm_is_protected(mm) && pte_present(res)) + uv_convert_from_secure(pte_val(res) & PAGE_MASK); + return res; } #define __HAVE_ARCH_PTEP_SET_WRPROTECT diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index 9e988543201f..1b97230a57ba 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -15,6 +15,7 @@ #include #include #include +#include #define UVC_RC_EXECUTED 0x0001 #define UVC_RC_INV_CMD 0x0002 @@ -24,6 +25,10 @@ #define UVC_CMD_QUI 0x0001 #define UVC_CMD_INIT_UV 0x000f +#define UVC_CMD_CONV_TO_SEC_STOR 0x0200 +#define UVC_CMD_CONV_FROM_SEC_STOR 0x0201 +#define UVC_CMD_PIN_PAGE_SHARED 0x0341 +#define UVC_CMD_UNPIN_PAGE_SHARED 0x0342 #define UVC_CMD_SET_SHARED_ACCESS 0x1000 #define UVC_CMD_REMOVE_SHARED_ACCESS 0x1001 @@ -31,8 +36,12 @@ enum uv_cmds_inst { BIT_UVC_CMD_QUI = 0, BIT_UVC_CMD_INIT_UV = 1, + BIT_UVC_CMD_CONV_TO_SEC_STOR = 6, + BIT_UVC_CMD_CONV_FROM_SEC_STOR = 7, BIT_UVC_CMD_SET_SHARED_ACCESS = 8, BIT_UVC_CMD_REMOVE_SHARED_ACCESS = 9, + BIT_UVC_CMD_PIN_PAGE_SHARED = 21, + BIT_UVC_CMD_UNPIN_PAGE_SHARED = 22, }; struct uv_cb_header { @@ -69,6 +78,19 @@ struct uv_cb_init { u64 reserved28[4]; } __packed __aligned(8); +struct uv_cb_cts { + struct uv_cb_header header; + u64 reserved08[2]; + u64 guest_handle; + u64 gaddr; +} __packed __aligned(8); + +struct uv_cb_cfs { + struct uv_cb_header header; + u64 reserved08[2]; + u64 paddr; +} __packed __aligned(8); + struct uv_cb_share { struct uv_cb_header header; u64 reserved08[3]; @@ -169,12 +191,42 @@ static inline int is_prot_virt_host(void) return prot_virt_host; } +int uv_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb); +int uv_convert_from_secure(unsigned long paddr); + +static inline int uv_convert_to_secure(struct gmap *gmap, unsigned long gaddr) +{ + struct uv_cb_cts uvcb = { + .header.cmd = UVC_CMD_CONV_TO_SEC_STOR, + .header.len = sizeof(uvcb), + .guest_handle = gmap->guest_handle, + .gaddr = gaddr, + }; + + return uv_make_secure(gmap, gaddr, &uvcb); +} + void setup_uv(void); void adjust_to_uv_max(unsigned long *vmax); #else #define is_prot_virt_host() 0 static inline void setup_uv(void) {} static inline void adjust_to_uv_max(unsigned long *vmax) {} + +static inline int uv_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb) +{ + return 0; +} + +static inline int uv_convert_from_secure(unsigned long paddr) +{ + return 0; +} + +static inline int uv_convert_to_secure(struct gmap *gmap, unsigned long gaddr) +{ + return 0; +} #endif #if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) || \ diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index a06a628a88da..15ac598a3d8d 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -9,6 +9,8 @@ #include #include #include +#include +#include #include #include #include @@ -99,4 +101,174 @@ void adjust_to_uv_max(unsigned long *vmax) if (prot_virt_host && *vmax > uv_info.max_sec_stor_addr) *vmax = uv_info.max_sec_stor_addr; } + +static int __uv_pin_shared(unsigned long paddr) +{ + struct uv_cb_cfs uvcb = { + .header.cmd = UVC_CMD_PIN_PAGE_SHARED, + .header.len = sizeof(uvcb), + .paddr = paddr, + }; + + if (uv_call(0, (u64)&uvcb)) + return -EINVAL; + return 0; +} + +/* + * Requests the Ultravisor to encrypt a guest page and make it + * accessible to the host for paging (export). + * + * @paddr: Absolute host address of page to be exported + */ +int uv_convert_from_secure(unsigned long paddr) +{ + struct uv_cb_cfs uvcb = { + .header.cmd = UVC_CMD_CONV_FROM_SEC_STOR, + .header.len = sizeof(uvcb), + .paddr = paddr + }; + + uv_call(0, (u64)&uvcb); + + if (uvcb.header.rc == 1 || uvcb.header.rc == 0x107) + return 0; + return -EINVAL; +} + +static int expected_page_refs(struct page *page) +{ + int res; + + res = page_mapcount(page); + if (PageSwapCache(page)) + res++; + else if (page_mapping(page)) { + res++; + if (page_has_private(page)) + res++; + } + return res; +} + +struct conv_params { + struct uv_cb_header *uvcb; + struct page *page; +}; + +static int make_secure_pte(pte_t *ptep, unsigned long addr, void *data) +{ + struct conv_params *params = data; + pte_t entry = READ_ONCE(*ptep); + struct page *page; + int expected, rc = 0; + + if (!pte_present(entry)) + return -ENXIO; + if (pte_val(entry) & (_PAGE_INVALID | _PAGE_PROTECT)) + return -ENXIO; + + page = pte_page(entry); + if (page != params->page) + return -ENXIO; + + if (PageWriteback(page)) + return -EAGAIN; + expected = expected_page_refs(page); + if (!page_ref_freeze(page, expected)) + return -EBUSY; + set_bit(PG_arch_1, &page->flags); + rc = uv_call(0, (u64)params->uvcb); + page_ref_unfreeze(page, expected); + if (rc) + rc = (params->uvcb->rc == 0x10a) ? -ENXIO : -EINVAL; + return rc; +} + +/* + * Requests the Ultravisor to make a page accessible to a guest. + * If it's brought in the first time, it will be cleared. If + * it has been exported before, it will be decrypted and integrity + * checked. + * + * @gmap: Guest mapping + * @gaddr: Guest 2 absolute address to be imported + */ +int uv_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb) +{ + struct conv_params params = { .uvcb = uvcb }; + struct vm_area_struct *vma; + unsigned long uaddr; + int rc, local_drain = 0; + +again: + rc = -EFAULT; + down_read(&gmap->mm->mmap_sem); + + uaddr = __gmap_translate(gmap, gaddr); + if (IS_ERR_VALUE(uaddr)) + goto out; + vma = find_vma(gmap->mm, uaddr); + if (!vma) + goto out; + if (is_vm_hugetlb_page(vma)) + goto out; + + rc = -ENXIO; + params.page = follow_page(vma, uaddr, FOLL_WRITE | FOLL_NOWAIT); + if (IS_ERR_OR_NULL(params.page)) + goto out; + + lock_page(params.page); + rc = apply_to_page_range(gmap->mm, uaddr, PAGE_SIZE, make_secure_pte, ¶ms); + unlock_page(params.page); +out: + up_read(&gmap->mm->mmap_sem); + + if (rc == -EBUSY) { + if (local_drain) { + lru_add_drain_all(); + return -EAGAIN; + } + lru_add_drain(); + local_drain = 1; + goto again; + } else if (rc == -ENXIO) { + if (gmap_fault(gmap, gaddr, FAULT_FLAG_WRITE)) + return -EFAULT; + return -EAGAIN; + } + return rc; +} +EXPORT_SYMBOL_GPL(uv_make_secure); + +/** + * To be called with the page locked or with an extra reference! + */ +int arch_make_page_accessible(struct page *page) +{ + int rc = 0; + + if (PageHuge(page)) + return 0; + + if (!test_bit(PG_arch_1, &page->flags)) + return 0; + + rc = __uv_pin_shared(page_to_phys(page)); + if (!rc) { + clear_bit(PG_arch_1, &page->flags); + return 0; + } + + rc = uv_convert_from_secure(page_to_phys(page)); + if (!rc) { + clear_bit(PG_arch_1, &page->flags); + return 0; + } + + return rc; +} +EXPORT_SYMBOL_GPL(arch_make_page_accessible); + #endif