1 use crate::arch::mm::LockedFrameAllocator; 2 use crate::arch::mm::PageMapper; 3 use crate::arch::MMArch; 4 use crate::mm::page::EntryFlags; 5 use crate::mm::{PageTableKind, PhysAddr, VirtAddr}; 6 use crate::smp::core::smp_get_processor_id; 7 use crate::smp::cpu::AtomicProcessorId; 8 use crate::smp::cpu::ProcessorId; 9 use core::sync::atomic::{compiler_fence, AtomicUsize, Ordering}; 10 use system_error::SystemError; 11 use x86::msr; 12 13 /// Check if MTRR is supported 14 pub fn check_ept_features() -> Result<(), SystemError> { 15 const MTRR_ENABLE_BIT: u64 = 1 << 11; 16 let ia32_mtrr_def_type = unsafe { msr::rdmsr(msr::IA32_MTRR_DEF_TYPE) }; 17 if (ia32_mtrr_def_type & MTRR_ENABLE_BIT) == 0 { 18 return Err(SystemError::ENOSYS); 19 } 20 Ok(()) 21 } 22 23 // pub fn ept_build_mtrr_map() -> Result<(), SystemError> { 24 // let ia32_mtrr_cap = unsafe { msr::rdmsr(msr::IA32_MTRRCAP) }; 25 // Ok(()) 26 // } 27 28 /// 标志当前没有处理器持有内核映射器的锁 29 /// 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 30 const EPT_MAPPER_NO_PROCESSOR: ProcessorId = ProcessorId::INVALID; 31 /// 当前持有内核映射器锁的处理器 32 static EPT_MAPPER_LOCK_OWNER: AtomicProcessorId = AtomicProcessorId::new(EPT_MAPPER_NO_PROCESSOR); 33 /// 内核映射器的锁计数器 34 static EPT_MAPPER_LOCK_COUNT: AtomicUsize = AtomicUsize::new(0); 35 36 pub struct EptMapper { 37 /// EPT页表映射器 38 mapper: PageMapper, 39 /// 标记当前映射器是否为只读 40 readonly: bool, 41 // EPT页表根地址 42 // root_hpa: PhysAddr, 43 } 44 45 impl EptMapper { 46 fn lock_cpu(cpuid: ProcessorId, mapper: PageMapper) -> Self { 47 loop { 48 match EPT_MAPPER_LOCK_OWNER.compare_exchange_weak( 49 EPT_MAPPER_NO_PROCESSOR, 50 cpuid, 51 Ordering::Acquire, 52 Ordering::Relaxed, 53 ) { 54 Ok(_) => break, 55 // 当前处理器已经持有了锁 56 Err(id) if id == cpuid => break, 57 // either CAS failed, or some other hardware thread holds the lock 58 Err(_) => core::hint::spin_loop(), 59 } 60 } 61 62 let prev_count = EPT_MAPPER_LOCK_COUNT.fetch_add(1, Ordering::Relaxed); 63 compiler_fence(Ordering::Acquire); 64 65 // 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 66 let readonly = prev_count > 0; 67 68 return Self { mapper, readonly }; 69 } 70 71 /// @brief 锁定内核映射器, 并返回一个内核映射器对象 72 #[inline(always)] 73 pub fn lock() -> Self { 74 let cpuid = smp_get_processor_id(); 75 let mapper = unsafe { PageMapper::current(PageTableKind::EPT, LockedFrameAllocator) }; 76 return Self::lock_cpu(cpuid, mapper); 77 } 78 79 /// 映射guest physical addr(gpa)到指定的host physical addr(hpa)。 80 /// 81 /// ## 参数 82 /// 83 /// - `gpa`: 要映射的guest physical addr 84 /// - `hpa`: 要映射的host physical addr 85 /// - `flags`: 页面标志 86 /// 87 /// ## 返回 88 /// 89 /// - 成功：返回Ok(()) 90 /// - 失败： 如果当前映射器为只读，则返回EAGAIN_OR_EWOULDBLOCK 91 pub unsafe fn walk( 92 &mut self, 93 gpa: u64, 94 hpa: u64, 95 flags: EntryFlags<MMArch>, 96 ) -> Result<(), SystemError> { 97 if self.readonly { 98 return Err(SystemError::EAGAIN_OR_EWOULDBLOCK); 99 } 100 self.mapper 101 .map_phys( 102 VirtAddr::new(gpa as usize), 103 PhysAddr::new(hpa as usize), 104 flags, 105 ) 106 .unwrap() 107 .flush(); 108 return Ok(()); 109 } 110 111 // fn get_ept_index(addr: u64, level: usize) -> u64 { 112 // let pt64_level_shift = PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS; 113 // (addr >> pt64_level_shift) & ((1 << PT64_LEVEL_BITS) - 1) 114 // } 115 } 116