asm/xen/page.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef _ASM_X86_XEN_PAGE_H
0003 #define _ASM_X86_XEN_PAGE_H
0004
0005 #include <linux/kernel.h>
0006 #include <linux/types.h>
0007 #include <linux/spinlock.h>
0008 #include <linux/pfn.h>
0009 #include <linux/mm.h>
0010 #include <linux/device.h>
0011
0012 #include <asm/extable.h>
0013 #include <asm/page.h>
0014
0015 #include <xen/interface/xen.h>
0016 #include <xen/interface/grant_table.h>
0017 #include <xen/features.h>
0018
0019 /* Xen machine address */
0020 typedef struct xmaddr {
0021     phys_addr_t maddr;
0022 } xmaddr_t;
0023
0024 /* Xen pseudo-physical address */
0025 typedef struct xpaddr {
0026     phys_addr_t paddr;
0027 } xpaddr_t;
0028
0029 #ifdef CONFIG_X86_64
0030 #define XEN_PHYSICAL_MASK   __sme_clr((1UL << 52) - 1)
0031 #else
0032 #define XEN_PHYSICAL_MASK   __PHYSICAL_MASK
0033 #endif
0034
0035 #define XEN_PTE_MFN_MASK    ((pteval_t)(((signed long)PAGE_MASK) & \
0036                         XEN_PHYSICAL_MASK))
0037
0038 #define XMADDR(x)   ((xmaddr_t) { .maddr = (x) })
0039 #define XPADDR(x)   ((xpaddr_t) { .paddr = (x) })
0040
0041 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
0042 #define INVALID_P2M_ENTRY   (~0UL)
0043 #define FOREIGN_FRAME_BIT   (1UL<<(BITS_PER_LONG-1))
0044 #define IDENTITY_FRAME_BIT  (1UL<<(BITS_PER_LONG-2))
0045 #define FOREIGN_FRAME(m)    ((m) | FOREIGN_FRAME_BIT)
0046 #define IDENTITY_FRAME(m)   ((m) | IDENTITY_FRAME_BIT)
0047
0048 #define P2M_PER_PAGE        (PAGE_SIZE / sizeof(unsigned long))
0049
0050 extern unsigned long *machine_to_phys_mapping;
0051 extern unsigned long  machine_to_phys_nr;
0052 extern unsigned long *xen_p2m_addr;
0053 extern unsigned long  xen_p2m_size;
0054 extern unsigned long  xen_max_p2m_pfn;
0055
0056 extern int xen_alloc_p2m_entry(unsigned long pfn);
0057
0058 extern unsigned long get_phys_to_machine(unsigned long pfn);
0059 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
0060 extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
0061 extern unsigned long __init set_phys_range_identity(unsigned long pfn_s,
0062                             unsigned long pfn_e);
0063
0064 #ifdef CONFIG_XEN_PV
0065 extern int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
0066                    struct gnttab_map_grant_ref *kmap_ops,
0067                    struct page **pages, unsigned int count);
0068 extern int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
0069                      struct gnttab_unmap_grant_ref *kunmap_ops,
0070                      struct page **pages, unsigned int count);
0071 #else
0072 static inline int
0073 set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
0074             struct gnttab_map_grant_ref *kmap_ops,
0075             struct page **pages, unsigned int count)
0076 {
0077     return 0;
0078 }
0079
0080 static inline int
0081 clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
0082               struct gnttab_unmap_grant_ref *kunmap_ops,
0083               struct page **pages, unsigned int count)
0084 {
0085     return 0;
0086 }
0087 #endif
0088
0089 /*
0090  * Helper functions to write or read unsigned long values to/from
0091  * memory, when the access may fault.
0092  */
0093 static inline int xen_safe_write_ulong(unsigned long *addr, unsigned long val)
0094 {
0095     int ret = 0;
0096
0097     asm volatile("1: mov %[val], %[ptr]\n"
0098              "2:\n"
0099              _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %[ret])
0100              : [ret] "+r" (ret), [ptr] "=m" (*addr)
0101              : [val] "r" (val));
0102
0103     return ret;
0104 }
0105
0106 static inline int xen_safe_read_ulong(const unsigned long *addr,
0107                       unsigned long *val)
0108 {
0109     unsigned long rval = ~0ul;
0110     int ret = 0;
0111
0112     asm volatile("1: mov %[ptr], %[rval]\n"
0113              "2:\n"
0114              _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %[ret])
0115              : [ret] "+r" (ret), [rval] "+r" (rval)
0116              : [ptr] "m" (*addr));
0117     *val = rval;
0118
0119     return ret;
0120 }
0121
0122 #ifdef CONFIG_XEN_PV
0123 /*
0124  * When to use pfn_to_mfn(), __pfn_to_mfn() or get_phys_to_machine():
0125  * - pfn_to_mfn() returns either INVALID_P2M_ENTRY or the mfn. No indicator
0126  *   bits (identity or foreign) are set.
0127  * - __pfn_to_mfn() returns the found entry of the p2m table. A possibly set
0128  *   identity or foreign indicator will be still set. __pfn_to_mfn() is
0129  *   encapsulating get_phys_to_machine() which is called in special cases only.
0130  * - get_phys_to_machine() is to be called by __pfn_to_mfn() only in special
0131  *   cases needing an extended handling.
0132  */
0133 static inline unsigned long __pfn_to_mfn(unsigned long pfn)
0134 {
0135     unsigned long mfn;
0136
0137     if (pfn < xen_p2m_size)
0138         mfn = xen_p2m_addr[pfn];
0139     else if (unlikely(pfn < xen_max_p2m_pfn))
0140         return get_phys_to_machine(pfn);
0141     else
0142         return IDENTITY_FRAME(pfn);
0143
0144     if (unlikely(mfn == INVALID_P2M_ENTRY))
0145         return get_phys_to_machine(pfn);
0146
0147     return mfn;
0148 }
0149 #else
0150 static inline unsigned long __pfn_to_mfn(unsigned long pfn)
0151 {
0152     return pfn;
0153 }
0154 #endif
0155
0156 static inline unsigned long pfn_to_mfn(unsigned long pfn)
0157 {
0158     unsigned long mfn;
0159
0160     /*
0161      * Some x86 code are still using pfn_to_mfn instead of
0162      * pfn_to_mfn. This will have to be removed when we figured
0163      * out which call.
0164      */
0165     if (xen_feature(XENFEAT_auto_translated_physmap))
0166         return pfn;
0167
0168     mfn = __pfn_to_mfn(pfn);
0169
0170     if (mfn != INVALID_P2M_ENTRY)
0171         mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
0172
0173     return mfn;
0174 }
0175
0176 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
0177 {
0178     if (xen_feature(XENFEAT_auto_translated_physmap))
0179         return 1;
0180
0181     return __pfn_to_mfn(pfn) != INVALID_P2M_ENTRY;
0182 }
0183
0184 static inline unsigned long mfn_to_pfn_no_overrides(unsigned long mfn)
0185 {
0186     unsigned long pfn;
0187     int ret;
0188
0189     if (unlikely(mfn >= machine_to_phys_nr))
0190         return ~0;
0191
0192     /*
0193      * The array access can fail (e.g., device space beyond end of RAM).
0194      * In such cases it doesn't matter what we return (we return garbage),
0195      * but we must handle the fault without crashing!
0196      */
0197     ret = xen_safe_read_ulong(&machine_to_phys_mapping[mfn], &pfn);
0198     if (ret < 0)
0199         return ~0;
0200
0201     return pfn;
0202 }
0203
0204 static inline unsigned long mfn_to_pfn(unsigned long mfn)
0205 {
0206     unsigned long pfn;
0207
0208     /*
0209      * Some x86 code are still using mfn_to_pfn instead of
0210      * gfn_to_pfn. This will have to be removed when we figure
0211      * out which call.
0212      */
0213     if (xen_feature(XENFEAT_auto_translated_physmap))
0214         return mfn;
0215
0216     pfn = mfn_to_pfn_no_overrides(mfn);
0217     if (__pfn_to_mfn(pfn) != mfn)
0218         pfn = ~0;
0219
0220     /*
0221      * pfn is ~0 if there are no entries in the m2p for mfn or the
0222      * entry doesn't map back to the mfn.
0223      */
0224     if (pfn == ~0 && __pfn_to_mfn(mfn) == IDENTITY_FRAME(mfn))
0225         pfn = mfn;
0226
0227     return pfn;
0228 }
0229
0230 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
0231 {
0232     unsigned offset = phys.paddr & ~PAGE_MASK;
0233     return XMADDR(PFN_PHYS(pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
0234 }
0235
0236 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
0237 {
0238     unsigned offset = machine.maddr & ~PAGE_MASK;
0239     return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
0240 }
0241
0242 /* Pseudo-physical <-> Guest conversion */
0243 static inline unsigned long pfn_to_gfn(unsigned long pfn)
0244 {
0245     if (xen_feature(XENFEAT_auto_translated_physmap))
0246         return pfn;
0247     else
0248         return pfn_to_mfn(pfn);
0249 }
0250
0251 static inline unsigned long gfn_to_pfn(unsigned long gfn)
0252 {
0253     if (xen_feature(XENFEAT_auto_translated_physmap))
0254         return gfn;
0255     else
0256         return mfn_to_pfn(gfn);
0257 }
0258
0259 /* Pseudo-physical <-> Bus conversion */
0260 #define pfn_to_bfn(pfn)     pfn_to_gfn(pfn)
0261 #define bfn_to_pfn(bfn)     gfn_to_pfn(bfn)
0262
0263 /*
0264  * We detect special mappings in one of two ways:
0265  *  1. If the MFN is an I/O page then Xen will set the m2p entry
0266  *     to be outside our maximum possible pseudophys range.
0267  *  2. If the MFN belongs to a different domain then we will certainly
0268  *     not have MFN in our p2m table. Conversely, if the page is ours,
0269  *     then we'll have p2m(m2p(MFN))==MFN.
0270  * If we detect a special mapping then it doesn't have a 'struct page'.
0271  * We force !pfn_valid() by returning an out-of-range pointer.
0272  *
0273  * NB. These checks require that, for any MFN that is not in our reservation,
0274  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
0275  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
0276  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
0277  *
0278  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
0279  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
0280  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
0281  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
0282  */
0283 static inline unsigned long bfn_to_local_pfn(unsigned long mfn)
0284 {
0285     unsigned long pfn;
0286
0287     if (xen_feature(XENFEAT_auto_translated_physmap))
0288         return mfn;
0289
0290     pfn = mfn_to_pfn(mfn);
0291     if (__pfn_to_mfn(pfn) != mfn)
0292         return -1; /* force !pfn_valid() */
0293     return pfn;
0294 }
0295
0296 /* VIRT <-> MACHINE conversion */
0297 #define virt_to_machine(v)  (phys_to_machine(XPADDR(__pa(v))))
0298 #define virt_to_pfn(v)          (PFN_DOWN(__pa(v)))
0299 #define virt_to_mfn(v)      (pfn_to_mfn(virt_to_pfn(v)))
0300 #define mfn_to_virt(m)      (__va(mfn_to_pfn(m) << PAGE_SHIFT))
0301
0302 /* VIRT <-> GUEST conversion */
0303 #define virt_to_gfn(v)      (pfn_to_gfn(virt_to_pfn(v)))
0304 #define gfn_to_virt(g)      (__va(gfn_to_pfn(g) << PAGE_SHIFT))
0305
0306 static inline unsigned long pte_mfn(pte_t pte)
0307 {
0308     return (pte.pte & XEN_PTE_MFN_MASK) >> PAGE_SHIFT;
0309 }
0310
0311 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
0312 {
0313     pte_t pte;
0314
0315     pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
0316             massage_pgprot(pgprot);
0317
0318     return pte;
0319 }
0320
0321 static inline pteval_t pte_val_ma(pte_t pte)
0322 {
0323     return pte.pte;
0324 }
0325
0326 static inline pte_t __pte_ma(pteval_t x)
0327 {
0328     return (pte_t) { .pte = x };
0329 }
0330
0331 #define pmd_val_ma(v) ((v).pmd)
0332 #ifdef __PAGETABLE_PUD_FOLDED
0333 #define pud_val_ma(v) ((v).p4d.pgd.pgd)
0334 #else
0335 #define pud_val_ma(v) ((v).pud)
0336 #endif
0337 #define __pmd_ma(x) ((pmd_t) { (x) } )
0338
0339 #ifdef __PAGETABLE_P4D_FOLDED
0340 #define p4d_val_ma(x)   ((x).pgd.pgd)
0341 #else
0342 #define p4d_val_ma(x)   ((x).p4d)
0343 #endif
0344
0345 xmaddr_t arbitrary_virt_to_machine(void *address);
0346 unsigned long arbitrary_virt_to_mfn(void *vaddr);
0347 void make_lowmem_page_readonly(void *vaddr);
0348 void make_lowmem_page_readwrite(void *vaddr);
0349
0350 static inline bool xen_arch_need_swiotlb(struct device *dev,
0351                      phys_addr_t phys,
0352                      dma_addr_t dev_addr)
0353 {
0354     return false;
0355 }
0356
0357 #endif /* _ASM_X86_XEN_PAGE_H */