1 use crate::arch::mm::LockedFrameAllocator; 2 use crate::arch::mm::PageMapper; 3 use crate::arch::MMArch; 4 use crate::mm::page::PageFlags; 5 use crate::mm::{PageTableKind, PhysAddr, VirtAddr}; 6 use crate::smp::core::smp_get_processor_id; 7 use core::sync::atomic::{compiler_fence, AtomicUsize, Ordering}; 8 use system_error::SystemError; 9 use x86::msr; 10 11 /// Check if MTRR is supported 12 pub fn check_ept_features() -> Result<(), SystemError> { 13 const MTRR_ENABLE_BIT: u64 = 1 << 11; 14 let ia32_mtrr_def_type = unsafe { msr::rdmsr(msr::IA32_MTRR_DEF_TYPE) }; 15 if (ia32_mtrr_def_type & MTRR_ENABLE_BIT) == 0 { 16 return Err(SystemError::EOPNOTSUPP_OR_ENOTSUP); 17 } 18 Ok(()) 19 } 20 21 // pub fn ept_build_mtrr_map() -> Result<(), SystemError> { 22 // let ia32_mtrr_cap = unsafe { msr::rdmsr(msr::IA32_MTRRCAP) }; 23 // Ok(()) 24 // } 25 26 /// 标志当前没有处理器持有内核映射器的锁 27 /// 之所以需要这个标志，是因为AtomicUsize::new(0)会把0当作一个处理器的id 28 const EPT_MAPPER_NO_PROCESSOR: usize = !0; 29 /// 当前持有内核映射器锁的处理器 30 static EPT_MAPPER_LOCK_OWNER: AtomicUsize = AtomicUsize::new(EPT_MAPPER_NO_PROCESSOR); 31 /// 内核映射器的锁计数器 32 static EPT_MAPPER_LOCK_COUNT: AtomicUsize = AtomicUsize::new(0); 33 34 pub struct EptMapper { 35 /// EPT页表映射器 36 mapper: PageMapper, 37 /// 标记当前映射器是否为只读 38 readonly: bool, 39 // EPT页表根地址 40 // root_hpa: PhysAddr, 41 } 42 43 impl EptMapper { 44 fn lock_cpu(cpuid: usize, mapper: PageMapper) -> Self { 45 loop { 46 match EPT_MAPPER_LOCK_OWNER.compare_exchange_weak( 47 EPT_MAPPER_NO_PROCESSOR, 48 cpuid, 49 Ordering::Acquire, 50 Ordering::Relaxed, 51 ) { 52 Ok(_) => break, 53 // 当前处理器已经持有了锁 54 Err(id) if id == cpuid => break, 55 // either CAS failed, or some other hardware thread holds the lock 56 Err(_) => core::hint::spin_loop(), 57 } 58 } 59 60 let prev_count = EPT_MAPPER_LOCK_COUNT.fetch_add(1, Ordering::Relaxed); 61 compiler_fence(Ordering::Acquire); 62 63 // 本地核心已经持有过锁，因此标记当前加锁获得的映射器为只读 64 let readonly = prev_count > 0; 65 66 return Self { mapper, readonly }; 67 } 68 69 /// @brief 锁定内核映射器, 并返回一个内核映射器对象 70 #[inline(always)] 71 pub fn lock() -> Self { 72 let cpuid = smp_get_processor_id() as usize; 73 let mapper = unsafe { PageMapper::current(PageTableKind::EPT, LockedFrameAllocator) }; 74 return Self::lock_cpu(cpuid, mapper); 75 } 76 77 /// 映射guest physical addr(gpa)到指定的host physical addr(hpa)。 78 /// 79 /// ## 参数 80 /// 81 /// - `gpa`: 要映射的guest physical addr 82 /// - `hpa`: 要映射的host physical addr 83 /// - `flags`: 页面标志 84 /// 85 /// ## 返回 86 /// 87 /// - 成功：返回Ok(()) 88 /// - 失败： 如果当前映射器为只读，则返回EAGAIN_OR_EWOULDBLOCK 89 pub unsafe fn walk( 90 &mut self, 91 gpa: u64, 92 hpa: u64, 93 flags: PageFlags<MMArch>, 94 ) -> Result<(), SystemError> { 95 if self.readonly { 96 return Err(SystemError::EAGAIN_OR_EWOULDBLOCK); 97 } 98 self.mapper 99 .map_phys( 100 VirtAddr::new(gpa as usize), 101 PhysAddr::new(hpa as usize), 102 flags, 103 ) 104 .unwrap() 105 .flush(); 106 return Ok(()); 107 } 108 109 // fn get_ept_index(addr: u64, level: usize) -> u64 { 110 // let pt64_level_shift = PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS; 111 // (addr >> pt64_level_shift) & ((1 << PT64_LEVEL_BITS) - 1) 112 // } 113 } 114