1 /* 2 * Async PF test. For the test to actually do anything it needs to be started 3 * in memory cgroup with 512M of memory and with more then 1G memory provided 4 * to the guest. 5 * 6 * To create cgroup do as root: 7 * mkdir /dev/cgroup 8 * mount -t cgroup none -omemory /dev/cgroup 9 * chmod a+rxw /dev/cgroup/ 10 * 11 * From a shell you will start qemu from: 12 * mkdir /dev/cgroup/1 13 * echo $$ > /dev/cgroup/1/tasks 14 * echo 512M > /dev/cgroup/1/memory.limit_in_bytes 15 * 16 */ 17 #include "x86/msr.h" 18 #include "x86/processor.h" 19 #include "x86/apic-defs.h" 20 #include "x86/apic.h" 21 #include "x86/desc.h" 22 #include "x86/isr.h" 23 #include "x86/vm.h" 24 25 #include "libcflat.h" 26 #include <stdint.h> 27 28 #define KVM_PV_REASON_PAGE_NOT_PRESENT 1 29 #define KVM_PV_REASON_PAGE_READY 2 30 31 #define MSR_KVM_ASYNC_PF_EN 0x4b564d02 32 33 #define KVM_ASYNC_PF_ENABLED (1 << 0) 34 #define KVM_ASYNC_PF_SEND_ALWAYS (1 << 1) 35 36 volatile uint32_t apf_reason __attribute__((aligned(64))); 37 char *buf; 38 volatile uint64_t i; 39 volatile uint64_t phys; 40 41 static inline uint32_t get_apf_reason(void) 42 { 43 uint32_t r = apf_reason; 44 apf_reason = 0; 45 return r; 46 } 47 48 static void pf_isr(struct ex_regs *r) 49 { 50 void* virt = (void*)((ulong)(buf+i) & ~(PAGE_SIZE-1)); 51 uint32_t reason = get_apf_reason(); 52 53 switch (reason) { 54 case 0: 55 report("unexpected #PF at %#lx", false, read_cr2()); 56 break; 57 case KVM_PV_REASON_PAGE_NOT_PRESENT: 58 phys = virt_to_phys_cr3(virt); 59 install_pte(phys_to_virt(read_cr3()), 1, virt, phys, 0); 60 write_cr3(read_cr3()); 61 report("Got not present #PF token %lx virt addr %p phys addr %#" PRIx64, 62 true, read_cr2(), virt, phys); 63 while(phys) { 64 safe_halt(); /* enables irq */ 65 irq_disable(); 66 } 67 break; 68 case KVM_PV_REASON_PAGE_READY: 69 report("Got present #PF token %lx", true, read_cr2()); 70 if ((uint32_t)read_cr2() == ~0) 71 break; 72 install_pte(phys_to_virt(read_cr3()), 1, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK, 0); 73 write_cr3(read_cr3()); 74 phys = 0; 75 break; 76 default: 77 report("unexpected async pf reason %d", false, reason); 78 break; 79 } 80 } 81 82 #define MEM 1ull*1024*1024*1024 83 84 int main(int ac, char **av) 85 { 86 int loop = 2; 87 88 setup_vm(); 89 setup_idt(); 90 printf("install handler\n"); 91 handle_exception(14, pf_isr); 92 apf_reason = 0; 93 printf("enable async pf\n"); 94 wrmsr(MSR_KVM_ASYNC_PF_EN, virt_to_phys((void*)&apf_reason) | 95 KVM_ASYNC_PF_SEND_ALWAYS | KVM_ASYNC_PF_ENABLED); 96 printf("alloc memory\n"); 97 buf = vmalloc(MEM); 98 irq_enable(); 99 while(loop--) { 100 printf("start loop\n"); 101 /* access a lot of memory to make host swap it out */ 102 for (i=0; i < MEM; i+=4096) 103 buf[i] = 1; 104 printf("end loop\n"); 105 } 106 irq_disable(); 107 108 return report_summary(); 109 } 110