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([94.75.70.14]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-53980fcdcd6sm1445087e87.153.2024.10.01.04.21.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Oct 2024 04:21:58 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 602c978b-7fe7-11ef-99a2-01e77a169b0f DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727781719; x=1728386519; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=rEDhR/79dEYv5D4TyLlFyLvFsiBEwyjBpV/3OO5dpSU=; b=k4PsK7z3CLY8bNcABin6UEQJ6WSU/VT/S4h2xysWzgr2CHWfi3mH2fyiMWnVSqmh3E snA65CUk0KVwixd02+K13xC3CxLk8o/zGokGVLaF6qtXRZZWuobUPxpmTBSuDV+GeTHx qQN/OnjewWquItcvKWxc4K/jZ7uvPuptP0jaEPyc/ALXDq/QvNy4LOIWyTTBiMsCTJMt kZ50rC53flnG6+KNxX6onvCyQ7N4Ts/VYZBSVAmPybJLw+CwTOdUd+sHSISSHvrmKApa KNLSjrQNkpk5dMsWnvQeDiiR1v1eyu+ssZH8IX49UAsglZz+zIriorHaIJnRe4VKmC1I Wf4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727781719; x=1728386519; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=rEDhR/79dEYv5D4TyLlFyLvFsiBEwyjBpV/3OO5dpSU=; b=ZoChhJ6qXH4vbovpA0xs4IPtE5DTuKI91iWgkk2HY+zRKQW/zgPM8MQhrh7tToK4kM akaKxFEUjcwOjkUO91+FOZr0C7ueChlq8O134gxpjmlicW8p4/olrH0Sry/9nv2J1cNT IyZ1kvbILpxz7330vo7GS3VBWvidx/uoqTdTWUfAc8SzqLlWSry4gVG4mCyWVLysz06c Z2D/bq5ySkUw1Gg96wIUWcCj4V4lFODf1YlCXGGV5V5kHJ1SgUmWAbC2DDWv5HPqaHpk 6XvpDFfIxh3ema5dJrHlhux+8xSzPOjzPzKk1hyzwG2wUbCwqOZH7GDS5sA+X0186STh CAmw== X-Gm-Message-State: AOJu0Yz+ykHQHwiF74eZo7u4WrPFxYvUxpTBD4Y2jHwpWZ3fOIXIMX5f E6tARUbSH/O+pJH6myI2tQVgBSpOPVc/AWQyOMw3BUnoX+SW/tTkIh+v9A== X-Google-Smtp-Source: AGHT+IF5oYkm6kQutY7dZnu3s/V97yqwlb1ymdYtJ2tGqcu6FzgRWFayCNvxKBycOmEJCNHwFQbEiA== X-Received: by 2002:a05:6512:6c2:b0:52f:1ef:bafe with SMTP id 2adb3069b0e04-5389fc3dc56mr8023263e87.22.1727781718743; Tue, 01 Oct 2024 04:21:58 -0700 (PDT) From: Oleksii Kurochko To: xen-devel@lists.xenproject.org Cc: Oleksii Kurochko , Alistair Francis , Bob Eshleman , Connor Davis , Andrew Cooper , Jan Beulich , Julien Grall , Stefano Stabellini Subject: [PATCH v9 1/2] xen/riscv: page table handling Date: Tue, 1 Oct 2024 13:21:21 +0200 Message-ID: <55244e67032d3a8f6064aeccff44ebb0138cafaf.1727781468.git.oleksii.kurochko@gmail.com> X-Mailer: git-send-email 2.46.1 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1727781758912116600 Implement map_pages_to_xen() which requires several functions to manage page tables and entries: - pt_update() - pt_mapping_level() - pt_update_entry() - pt_next_level() - pt_check_entry() To support these operations, add functions for creating, mapping, and unmapping Xen tables: - create_table() - map_table() - unmap_table() Introduce PTE_SMALL to indicate that 4KB mapping is needed and PTE_POPULATE. In addition introduce flush_tlb_range_va() for TLB flushing across CPUs after updating the PTE for the requested mapping. Signed-off-by: Oleksii Kurochko Reviewed-by: Jan Beulich --- Changes in V9: - fix indentation alignment for dprintk() in pt_check_entry(). - update the stale comment ( add explanation for XEN_TABLE_MAP_NOMEM and XEN_TABLE_MAP_NONE ) - change return type to bool for create_table() so it returns false when allocation is falied; otherwise - true. --- Changes in V8: - drop PTE_LEAF_MASK. - update the comment above pte_is_table(): drop table number and use just "the encoding of the permission bits". - declare pte_is_table() as static. - drop const from the argument of pte_is_table - drop the "const" comment before the argument of pte_is_mapping(). - update the comment above ASSERT() in pte_is_mapping() to : See pte_is_ta= ble(). - drop "const" from the return type of get_root_page(). - update the comment above "pt_check_entry()". - start the comment with capital letter. - update the way how PTE_ACCESS_MASK bits are cleared before being updated= by the value in flags. - use dprintk() instead of printk() in riscv/pt.c - introduce XEN_TABLE_MAP_NONE and XEN_TABLE_MAP_NOMEM instead of XEN_TABL= E_MAP_FAILED and correspondingly update part of the code of pt_next_level()'s return = value handling in pt_update_entry. - update type of virt to vaddr_t for pt_update_entry() --- Changes in V7: - rename PTE_XWV_BITS to PTE_LEAF_MASK. - drop PTE_XWV_MASK, PTE_RWX_MASK. - introduce PTE_ACCESS_MASK. - update the ASSERT and the comment about it in pte_is_mapping(). - add the same ASSERT as in pte_is_mapping() to pte_is_table(). - update the comment above pte_is_table(). - use PTE_ACCESS_MASK inside pte_is_{table,mapping} instead of encoding access bit explicitly. - define SATP_PPN_MASK using SATP{32,64}_PPN. - drop inclusion of #include in riscv/pt.c as xen/mm.h is included. - use pfn_to_paddr() in get_root_page() instead of open-coding of pfn_to_p= addr(). - update if the comment and the if (...) in pt_update_entry() above the ch= eck in case of pt_next_level() returns XEN_TABLE_MAP_FAILED. - update the the comment above pt_update(): drop unecessary mentioning of = INVALID_MFN and blanks inside parentheses. - drop "full stops" in printk(). - correct the condition in ASSERT() in map_pages_to_xen(). - clear permission bits before updating the permissions in pt_update_entry= (). --- Changes in V6: - update the commit message. - correct the comment above flush_tlb_range_va(). - add PTE_READABLE to the check of pte.rwx permissions in pte_is_mapping(). - s/printk/dprintk in pt_check_entry(). - drop unnecessary ASSERTS() in pt_check_entry(). - drop checking of PTE_VALID flags in /* Sanity check when removing a mapping */ because of the earlier check. - drop ASSERT(flags & PTE_POPULATE) in /* Sanity check when populating the= page-table */ section as in the earlier if it is checked. - pt_next_level() changes: - invert if ( alloc_tbl ) condition. - drop local variable ret. - pt_update_entry() changes: - invert definition of alloc_tbl. - update the comment inside "if ( rc =3D=3D XEN_TABLE_MAP_FAILED )". - drop else for mentioned above if (...). - clear some PTE flags before update. - s/xen_pt_lock/pt_lock - use PFN_DOWN() for vfn variable definition in pt_update(). - drop definition of PTE_{R,W,X}_MASK. - introduce PTE_XWV_BITS and PTE_XWV_MASK() for convenience and use them i= n if (...) in pt_update(). - update the comment above pt_update(). - change memset(&pte, 0x00, sizeof(pte)) to pte.pte =3D 0. - add the comment above pte_is_table(). - add ASSERT in pte_is_mapping() to check the cases which are reserved for= future use. --- Changes in V5: - s/xen_{un}map/{un}map - introduce PTE_SMALL instead of PTE_BLOCK. - update the comment above defintion of PTE_4K_PAGES. - code style fixes. - s/RV_STAGE1_MODE > SATP_MODE_SV48/RV_STAGE1_MODE > SATP_MODE_SV39 around DECLARE_OFFSETS macros. - change type of root_maddr from unsgined long to maddr_t. - drop duplicated check ( if (rc) break ) in pt_update() inside while cycl= e. - s/1U/1UL - put 'spin_unlock(&xen_pt_lock);' ahead of TLB flush in pt_update(). - update the commit message. - update the comment above ASSERT() in map_pages_to_xen() and also update the check within ASSERT() to check that flags has PTE_VALID bit set. - update the comment above pt_update() function. - add the comment inside pt_check_entry(). - update the TLB flushing region in pt_update(). - s/alloc_only/alloc_tbl --- Changes in V4: - update the commit message. - drop xen_ prefix for functions: xen_pt_update(), xen_pt_mapping_level(), xen_pt_update_entry(), xen_pt_next_level(), xen_pt_check_entry(). - drop 'select GENERIC_PT' for CONFIG_RISCV. There is no GENERIC_PT anymor= e. - update implementation of flush_xen_tlb_range_va and s/flush_xen_tlb_rang= e_va/flush_tlb_range_va - s/pte_get_mfn/mfn_from_pte. Others similar definitions I decided not to = touch as they were introduced before and this patter of naming such type of macro= s will be applied for newly introduced macros. - drop _PAGE_* definitions and use analogues of PTE_*. - introduce PTE_{W,X,R}_MASK and drop PAGE_{XN,W,X}_MASK. Also drop _PAGE_= {*}_BIT - introduce PAGE_HYPERVISOR_RX. - drop unused now l3_table_offset. - drop struct pt_t as it was used only for one function. If it will be nee= ded in the future pt_t will be re-introduced. - code styles fixes in pte_is_table(). drop level argument from t. - update implementation and prototype of pte_is_mapping(). - drop level argument from pt_next_level(). - introduce definition of SATP_PPN_MASK. - isolate PPN of CSR_SATP before shift by PAGE_SHIFT. - drop set_permission() functions as it is not used more then once. - update prototype of pt_check_entry(): drop level argument as it is not u= sed. - pt_check_entry(): - code style fixes - update the sanity check when modifying an entry - update the sanity check when when removing a mapping. - s/read_only/alloc_only. - code style fixes for pt_next_level(). - pt_update_entry() changes: - drop arch_level variable inisde pt_update_entry() - drop convertion near virt to paddr_t in DECLARE_OFFSETS(offsets, virt); - pull out "goto out inside first 'for' cycle. - drop braces for 'if' cases which has only one line. - ident 'out' label with one blank. - update the comment above alloc_only and also definition to take into account that if pte population was requested or not. - drop target variable and rename arch_target argument of the function to target. - pt_mapping_level() changes: - move the check if PTE_BLOCK should be mapped on the top of the functio= n. - change int i to unsigned int and update 'for' cycle correspondingly. - update prototye of pt_update(): - drop the comment above nr_mfns and drop const to be consistent with o= ther arguments. - always flush TLB at the end of the function as non-present entries can= be put in the TLB. - add fence before TLB flush to ensure that PTEs are all updated before = flushing. - s/XEN_TABLE_NORMAL_PAGE/XEN_TABLE_NORMAL - add a check in map_pages_to_xen() the mfn is not INVALID_MFN. - add the comment on top of pt_update() how mfn =3D INVALID_MFN is conside= red. - s/_PAGE_BLOCK/PTE_BLOCK. - add the comment with additional explanation for PTE_BLOCK. - drop defintion of FIRST_SIZE as it isn't used. --- Changes in V3: - new patch. ( Technically it is reworked version of the generic approach which I tried to suggest in the previous version ) --- xen/arch/riscv/Makefile | 1 + xen/arch/riscv/include/asm/flushtlb.h | 9 + xen/arch/riscv/include/asm/mm.h | 2 + xen/arch/riscv/include/asm/page.h | 80 ++++ xen/arch/riscv/include/asm/riscv_encoding.h | 2 + xen/arch/riscv/mm.c | 9 - xen/arch/riscv/pt.c | 421 ++++++++++++++++++++ 7 files changed, 515 insertions(+), 9 deletions(-) create mode 100644 xen/arch/riscv/pt.c diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile index 6832549133..a5eb2aed4b 100644 --- a/xen/arch/riscv/Makefile +++ b/xen/arch/riscv/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_EARLY_PRINTK) +=3D early_printk.o obj-y +=3D entry.o obj-y +=3D mm.o +obj-y +=3D pt.o obj-$(CONFIG_RISCV_64) +=3D riscv64/ obj-y +=3D sbi.o obj-y +=3D setup.o diff --git a/xen/arch/riscv/include/asm/flushtlb.h b/xen/arch/riscv/include= /asm/flushtlb.h index f4a735fd6c..43214f5e95 100644 --- a/xen/arch/riscv/include/asm/flushtlb.h +++ b/xen/arch/riscv/include/asm/flushtlb.h @@ -5,12 +5,21 @@ #include #include =20 +#include + /* Flush TLB of local processor for address va. */ static inline void flush_tlb_one_local(vaddr_t va) { asm volatile ( "sfence.vma %0" :: "r" (va) : "memory" ); } =20 +/* Flush a range of VA's hypervisor mappings from the TLB of all processor= s. */ +static inline void flush_tlb_range_va(vaddr_t va, size_t size) +{ + BUG_ON(!sbi_has_rfence()); + sbi_remote_sfence_vma(NULL, va, size); +} + /* * Filter the given set of CPUs, removing those that definitely flushed th= eir * TLB since @page_timestamp. diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/m= m.h index a0bdc2bc3a..ce1557bb27 100644 --- a/xen/arch/riscv/include/asm/mm.h +++ b/xen/arch/riscv/include/asm/mm.h @@ -42,6 +42,8 @@ static inline void *maddr_to_virt(paddr_t ma) #define virt_to_mfn(va) __virt_to_mfn(va) #define mfn_to_virt(mfn) __mfn_to_virt(mfn) =20 +#define mfn_from_pte(pte) maddr_to_mfn(pte_to_paddr(pte)) + struct page_info { /* Each frame can be threaded onto a doubly-linked list. */ diff --git a/xen/arch/riscv/include/asm/page.h b/xen/arch/riscv/include/asm= /page.h index eb79cb9409..89fa290697 100644 --- a/xen/arch/riscv/include/asm/page.h +++ b/xen/arch/riscv/include/asm/page.h @@ -21,6 +21,11 @@ #define XEN_PT_LEVEL_MAP_MASK(lvl) (~(XEN_PT_LEVEL_SIZE(lvl) - 1)) #define XEN_PT_LEVEL_MASK(lvl) (VPN_MASK << XEN_PT_LEVEL_SHIFT(lvl)) =20 +/* + * PTE format: + * | XLEN-1 10 | 9 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 + * PFN reserved for SW D A G U X W R V + */ #define PTE_VALID BIT(0, UL) #define PTE_READABLE BIT(1, UL) #define PTE_WRITABLE BIT(2, UL) @@ -34,15 +39,49 @@ #define PTE_LEAF_DEFAULT (PTE_VALID | PTE_READABLE | PTE_WRITAB= LE) #define PTE_TABLE (PTE_VALID) =20 +#define PAGE_HYPERVISOR_RO (PTE_VALID | PTE_READABLE) #define PAGE_HYPERVISOR_RW (PTE_VALID | PTE_READABLE | PTE_WRITAB= LE) +#define PAGE_HYPERVISOR_RX (PTE_VALID | PTE_READABLE | PTE_EXECUT= ABLE) =20 #define PAGE_HYPERVISOR PAGE_HYPERVISOR_RW =20 +/* + * The PTE format does not contain the following bits within itself; + * they are created artificially to inform the Xen page table + * handling algorithm. These bits should not be explicitly written + * to the PTE entry. + */ +#define PTE_SMALL BIT(10, UL) +#define PTE_POPULATE BIT(11, UL) + +#define PTE_ACCESS_MASK (PTE_READABLE | PTE_WRITABLE | PTE_EXECUTABLE) + /* Calculate the offsets into the pagetables for a given VA */ #define pt_linear_offset(lvl, va) ((va) >> XEN_PT_LEVEL_SHIFT(lvl)) =20 #define pt_index(lvl, va) (pt_linear_offset((lvl), (va)) & VPN_MASK) =20 +#define PAGETABLE_ORDER_MASK ((_AC(1, U) << PAGETABLE_ORDER) - 1) +#define TABLE_OFFSET(offs) (_AT(unsigned int, offs) & PAGETABLE_ORDER_MASK) + +#if RV_STAGE1_MODE > SATP_MODE_SV39 +#error "need to to update DECLARE_OFFSETS macros" +#else + +#define l0_table_offset(va) TABLE_OFFSET(pt_linear_offset(0, va)) +#define l1_table_offset(va) TABLE_OFFSET(pt_linear_offset(1, va)) +#define l2_table_offset(va) TABLE_OFFSET(pt_linear_offset(2, va)) + +/* Generate an array @var containing the offset for each level from @addr = */ +#define DECLARE_OFFSETS(var, addr) \ + const unsigned int var[] =3D { \ + l0_table_offset(addr), \ + l1_table_offset(addr), \ + l2_table_offset(addr), \ + } + +#endif + /* Page Table entry */ typedef struct { #ifdef CONFIG_RISCV_64 @@ -68,6 +107,47 @@ static inline bool pte_is_valid(pte_t p) return p.pte & PTE_VALID; } =20 +/* + * From the RISC-V spec: + * The V bit indicates whether the PTE is valid; if it is 0, all other b= its + * in the PTE are don=E2=80=99t-cares and may be used freely by software. + * + * If V=3D1 the encoding of PTE R/W/X bits could be find in "the encoding + * of the permission bits" table. + * + * The encoding of the permission bits table: + * X W R Meaning + * 0 0 0 Pointer to next level of page table. + * 0 0 1 Read-only page. + * 0 1 0 Reserved for future use. + * 0 1 1 Read-write page. + * 1 0 0 Execute-only page. + * 1 0 1 Read-execute page. + * 1 1 0 Reserved for future use. + * 1 1 1 Read-write-execute page. + */ +static inline bool pte_is_table(pte_t p) +{ + /* + * According to the spec if V=3D1 and W=3D1 then R also needs to be 1 = as + * R =3D 0 is reserved for future use ( look at the Table 4.5 ) so che= ck + * in ASSERT that if (V=3D=3D1 && W=3D=3D1) then R isn't 0. + * + * PAGE_HYPERVISOR_RW contains PTE_VALID too. + */ + ASSERT(((p.pte & PAGE_HYPERVISOR_RW) !=3D (PTE_VALID | PTE_WRITABLE))); + + return ((p.pte & (PTE_VALID | PTE_ACCESS_MASK)) =3D=3D PTE_VALID); +} + +static inline bool pte_is_mapping(pte_t p) +{ + /* See pte_is_table() */ + ASSERT(((p.pte & PAGE_HYPERVISOR_RW) !=3D (PTE_VALID | PTE_WRITABLE))); + + return (p.pte & PTE_VALID) && (p.pte & PTE_ACCESS_MASK); +} + static inline void invalidate_icache(void) { BUG_ON("unimplemented"); diff --git a/xen/arch/riscv/include/asm/riscv_encoding.h b/xen/arch/riscv/i= nclude/asm/riscv_encoding.h index 58abe5eccc..e31e94e77e 100644 --- a/xen/arch/riscv/include/asm/riscv_encoding.h +++ b/xen/arch/riscv/include/asm/riscv_encoding.h @@ -164,6 +164,7 @@ #define SSTATUS_SD SSTATUS64_SD #define SATP_MODE SATP64_MODE #define SATP_MODE_SHIFT SATP64_MODE_SHIFT +#define SATP_PPN_MASK SATP64_PPN =20 #define HGATP_PPN HGATP64_PPN #define HGATP_VMID_SHIFT HGATP64_VMID_SHIFT @@ -174,6 +175,7 @@ #define SSTATUS_SD SSTATUS32_SD #define SATP_MODE SATP32_MODE #define SATP_MODE_SHIFT SATP32_MODE_SHIFT +#define SATP_PPN_MASK SATP32_PPN =20 #define HGATP_PPN HGATP32_PPN #define HGATP_VMID_SHIFT HGATP32_VMID_SHIFT diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c index b8ff91cf4e..e8430def14 100644 --- a/xen/arch/riscv/mm.c +++ b/xen/arch/riscv/mm.c @@ -369,12 +369,3 @@ int destroy_xen_mappings(unsigned long s, unsigned lon= g e) BUG_ON("unimplemented"); return -1; } - -int map_pages_to_xen(unsigned long virt, - mfn_t mfn, - unsigned long nr_mfns, - unsigned int flags) -{ - BUG_ON("unimplemented"); - return -1; -} diff --git a/xen/arch/riscv/pt.c b/xen/arch/riscv/pt.c new file mode 100644 index 0000000000..cc5e2d3266 --- /dev/null +++ b/xen/arch/riscv/pt.c @@ -0,0 +1,421 @@ +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +static inline mfn_t get_root_page(void) +{ + paddr_t root_maddr =3D pfn_to_paddr(csr_read(CSR_SATP) & SATP_PPN_MASK= ); + + return maddr_to_mfn(root_maddr); +} + +/* + * Sanity check a page table entry about to be updated as per an (MFN,flag= s) + * tuple. + * See the comment about the possible combination of (mfn, flags) in + * the comment above pt_update(). + */ +static bool pt_check_entry(pte_t entry, mfn_t mfn, unsigned int flags) +{ + /* Sanity check when modifying an entry. */ + if ( (flags & PTE_VALID) && mfn_eq(mfn, INVALID_MFN) ) + { + /* We don't allow modifying an invalid entry. */ + if ( !pte_is_valid(entry) ) + { + dprintk(XENLOG_ERR, "Modifying invalid entry is not allowed\n"= ); + return false; + } + + /* We don't allow modifying a table entry */ + if ( pte_is_table(entry) ) + { + dprintk(XENLOG_ERR, "Modifying a table entry is not allowed\n"= ); + return false; + } + } + /* Sanity check when inserting a mapping */ + else if ( flags & PTE_VALID ) + { + /* + * We don't allow replacing any valid entry. + * + * Note that the function pt_update() relies on this + * assumption and will skip the TLB flush (when Svvptc + * extension will be ratified). The function will need + * to be updated if the check is relaxed. + */ + if ( pte_is_valid(entry) ) + { + if ( pte_is_mapping(entry) ) + dprintk(XENLOG_ERR, "Changing MFN for valid PTE is not all= owed (%#"PRI_mfn" -> %#"PRI_mfn")\n", + mfn_x(mfn_from_pte(entry)), mfn_x(mfn)); + else + dprintk(XENLOG_ERR, "Trying to replace table with mapping\= n"); + return false; + } + } + /* Sanity check when removing a mapping. */ + else if ( !(flags & PTE_POPULATE) ) + { + /* We should be here with an invalid MFN. */ + ASSERT(mfn_eq(mfn, INVALID_MFN)); + + /* We don't allow removing a table */ + if ( pte_is_table(entry) ) + { + dprintk(XENLOG_ERR, "Removing a table is not allowed\n"); + return false; + } + } + /* Sanity check when populating the page-table. No check so far. */ + else + { + /* We should be here with an invalid MFN */ + ASSERT(mfn_eq(mfn, INVALID_MFN)); + } + + return true; +} + +static pte_t *map_table(mfn_t mfn) +{ + /* + * During early boot, map_domain_page() may be unusable. Use the + * PMAP to map temporarily a page-table. + */ + if ( system_state =3D=3D SYS_STATE_early_boot ) + return pmap_map(mfn); + + return map_domain_page(mfn); +} + +static void unmap_table(const pte_t *table) +{ + /* + * During early boot, map_table() will not use map_domain_page() + * but the PMAP. + */ + if ( system_state =3D=3D SYS_STATE_early_boot ) + pmap_unmap(table); + else + unmap_domain_page(table); +} + +static bool create_table(pte_t *entry) +{ + mfn_t mfn; + void *p; + pte_t pte; + + if ( system_state !=3D SYS_STATE_early_boot ) + { + struct page_info *pg =3D alloc_domheap_page(NULL, 0); + + if ( pg =3D=3D NULL ) + return false; + + mfn =3D page_to_mfn(pg); + } + else + mfn =3D alloc_boot_pages(1, 1); + + p =3D map_table(mfn); + clear_page(p); + unmap_table(p); + + pte =3D pte_from_mfn(mfn, PTE_TABLE); + write_pte(entry, pte); + + return true; +} + +#define XEN_TABLE_MAP_NONE 0 +#define XEN_TABLE_MAP_NOMEM 1 +#define XEN_TABLE_SUPER_PAGE 2 +#define XEN_TABLE_NORMAL 3 + +/* + * Take the currently mapped table, find the corresponding entry, + * and map the next table, if available. + * + * The alloc_tbl parameters indicates whether intermediate tables should + * be allocated when not present. + * + * Return values: + * XEN_TABLE_MAP_NONE: a table allocation isn't permitted. + * XEN_TABLE_MAP_NOMEM: allocating a new page failed. + * XEN_TABLE_NORMAL: next level or leaf mapped normally. + * XEN_TABLE_SUPER_PAGE: The next entry points to a superpage. + */ +static int pt_next_level(bool alloc_tbl, pte_t **table, unsigned int offse= t) +{ + pte_t *entry; + mfn_t mfn; + + entry =3D *table + offset; + + if ( !pte_is_valid(*entry) ) + { + if ( !alloc_tbl ) + return XEN_TABLE_MAP_NONE; + + if ( !create_table(entry) ) + return XEN_TABLE_MAP_NOMEM; + } + + if ( pte_is_mapping(*entry) ) + return XEN_TABLE_SUPER_PAGE; + + mfn =3D mfn_from_pte(*entry); + + unmap_table(*table); + *table =3D map_table(mfn); + + return XEN_TABLE_NORMAL; +} + +/* Update an entry at the level @target. */ +static int pt_update_entry(mfn_t root, vaddr_t virt, + mfn_t mfn, unsigned int target, + unsigned int flags) +{ + int rc; + unsigned int level =3D HYP_PT_ROOT_LEVEL; + pte_t *table; + /* + * The intermediate page table shouldn't be allocated when MFN isn't + * valid and we are not populating page table. + * This means we either modify permissions or remove an entry, or + * inserting brand new entry. + * + * See the comment above pt_update() for an additional explanation abo= ut + * combinations of (mfn, flags). + */ + bool alloc_tbl =3D !mfn_eq(mfn, INVALID_MFN) || (flags & PTE_POPULATE); + pte_t pte, *entry; + + /* convenience aliases */ + DECLARE_OFFSETS(offsets, virt); + + table =3D map_table(root); + for ( ; level > target; level-- ) + { + rc =3D pt_next_level(alloc_tbl, &table, offsets[level]); + if ( rc =3D=3D XEN_TABLE_MAP_NOMEM ) + { + rc =3D -ENOMEM; + goto out; + } + + if ( rc =3D=3D XEN_TABLE_MAP_NONE ) + { + rc =3D 0; + goto out; + } + + if ( rc !=3D XEN_TABLE_NORMAL ) + break; + } + + if ( level !=3D target ) + { + dprintk(XENLOG_ERR, + "%s: Shattering superpage is not supported\n", __func__); + rc =3D -EOPNOTSUPP; + goto out; + } + + entry =3D table + offsets[level]; + + rc =3D -EINVAL; + if ( !pt_check_entry(*entry, mfn, flags) ) + goto out; + + /* We are removing the page */ + if ( !(flags & PTE_VALID) ) + /* + * There is also a check in pt_check_entry() which check that + * mfn=3DINVALID_MFN + */ + pte.pte =3D 0; + else + { + /* We are inserting a mapping =3D> Create new pte. */ + if ( !mfn_eq(mfn, INVALID_MFN) ) + pte =3D pte_from_mfn(mfn, PTE_VALID); + else /* We are updating the permission =3D> Copy the current pte. = */ + { + pte =3D *entry; + pte.pte &=3D ~PTE_ACCESS_MASK; + } + + /* update permission according to the flags */ + pte.pte |=3D (flags & PTE_ACCESS_MASK) | PTE_ACCESSED | PTE_DIRTY; + } + + write_pte(entry, pte); + + rc =3D 0; + + out: + unmap_table(table); + + return rc; +} + +/* Return the level where mapping should be done */ +static int pt_mapping_level(unsigned long vfn, mfn_t mfn, unsigned long nr, + unsigned int flags) +{ + unsigned int level =3D 0; + unsigned long mask; + unsigned int i; + + /* + * Use a larger mapping than 4K unless the caller specifically requests + * 4K mapping + */ + if ( unlikely(flags & PTE_SMALL) ) + return level; + + /* + * Don't take into account the MFN when removing mapping (i.e + * MFN_INVALID) to calculate the correct target order. + * + * `vfn` and `mfn` must be both superpage aligned. + * They are or-ed together and then checked against the size of + * each level. + * + * `left` ( variable declared in pt_update() ) is not included + * and checked separately to allow superpage mapping even if it + * is not properly aligned (the user may have asked to map 2MB + 4k). + */ + mask =3D !mfn_eq(mfn, INVALID_MFN) ? mfn_x(mfn) : 0; + mask |=3D vfn; + + for ( i =3D HYP_PT_ROOT_LEVEL; i !=3D 0; i-- ) + { + if ( !(mask & (BIT(XEN_PT_LEVEL_ORDER(i), UL) - 1)) && + (nr >=3D BIT(XEN_PT_LEVEL_ORDER(i), UL)) ) + { + level =3D i; + break; + } + } + + return level; +} + +static DEFINE_SPINLOCK(pt_lock); + +/* + * If `mfn` equals `INVALID_MFN`, it indicates that the following page tab= le + * update operation might be related to either: + * - populating the table (PTE_POPULATE will be set additionaly), + * - destroying a mapping (PTE_VALID=3D0), + * - modifying an existing mapping (PTE_VALID=3D1). + * + * If `mfn` !=3D INVALID_MFN and flags has PTE_VALID bit set then it means= that + * inserting will be done. + */ +static int pt_update(vaddr_t virt, mfn_t mfn, + unsigned long nr_mfns, unsigned int flags) +{ + int rc =3D 0; + unsigned long vfn =3D PFN_DOWN(virt); + unsigned long left =3D nr_mfns; + const mfn_t root =3D get_root_page(); + + /* + * It is bad idea to have mapping both writeable and + * executable. + * When modifying/creating mapping (i.e PTE_VALID is set), + * prevent any update if this happen. + */ + if ( (flags & PTE_VALID) && (flags & PTE_WRITABLE) && + (flags & PTE_EXECUTABLE) ) + { + dprintk(XENLOG_ERR, + "Mappings should not be both Writeable and Executable\n"); + return -EINVAL; + } + + if ( !IS_ALIGNED(virt, PAGE_SIZE) ) + { + dprintk(XENLOG_ERR, + "The virtual address is not aligned to the page-size\n"); + return -EINVAL; + } + + spin_lock(&pt_lock); + + while ( left ) + { + unsigned int order, level; + + level =3D pt_mapping_level(vfn, mfn, left, flags); + order =3D XEN_PT_LEVEL_ORDER(level); + + ASSERT(left >=3D BIT(order, UL)); + + rc =3D pt_update_entry(root, vfn << PAGE_SHIFT, mfn, level, flags); + if ( rc ) + break; + + vfn +=3D 1UL << order; + if ( !mfn_eq(mfn, INVALID_MFN) ) + mfn =3D mfn_add(mfn, 1UL << order); + + left -=3D (1UL << order); + } + + /* Ensure that PTEs are all updated before flushing */ + RISCV_FENCE(rw, rw); + + spin_unlock(&pt_lock); + + /* + * Always flush TLB at the end of the function as non-present entries + * can be put in the TLB. + * + * The remote fence operation applies to the entire address space if + * either: + * - start and size are both 0, or + * - size is equal to 2^XLEN-1. + * + * TODO: come up with something which will allow not to flash the enti= re + * address space. + */ + flush_tlb_range_va(0, 0); + + return rc; +} + +int map_pages_to_xen(unsigned long virt, + mfn_t mfn, + unsigned long nr_mfns, + unsigned int flags) +{ + /* + * Ensure that flags has PTE_VALID bit as map_pages_to_xen() is suppos= ed + * to create a mapping. + * + * Ensure that we have a valid MFN before proceeding. + * + * If the MFN is invalid, pt_update() might misinterpret the operation, + * treating it as either a population, a mapping destruction, + * or a mapping modification. + */ + ASSERT(!mfn_eq(mfn, INVALID_MFN) && (flags & PTE_VALID)); + + return pt_update(virt, mfn, nr_mfns, flags); +} --=20 2.46.1