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