1 // SPDX-License-Identifier: GPL-2.0 2 #include <fcntl.h> 3 #include <stdio.h> 4 #include <stdlib.h> 5 #include <string.h> 6 #include <sys/ioctl.h> 7 8 #include "test_util.h" 9 10 #include "kvm_util.h" 11 #include "processor.h" 12 13 static void guest_ins_port80(uint8_t *buffer, unsigned int count) 14 { 15 unsigned long end; 16 17 if (count == 2) 18 end = (unsigned long)buffer + 1; 19 else 20 end = (unsigned long)buffer + 8192; 21 22 asm volatile("cld; rep; insb" : "+D"(buffer), "+c"(count) : "d"(0x80) : "memory"); 23 GUEST_ASSERT_1(count == 0, count); 24 GUEST_ASSERT_2((unsigned long)buffer == end, buffer, end); 25 } 26 27 static void guest_code(void) 28 { 29 uint8_t buffer[8192]; 30 int i; 31 32 /* 33 * Special case tests. main() will adjust RCX 2 => 1 and 3 => 8192 to 34 * test that KVM doesn't explode when userspace modifies the "count" on 35 * a userspace I/O exit. KVM isn't required to play nice with the I/O 36 * itself as KVM doesn't support manipulating the count, it just needs 37 * to not explode or overflow a buffer. 38 */ 39 guest_ins_port80(buffer, 2); 40 guest_ins_port80(buffer, 3); 41 42 /* Verify KVM fills the buffer correctly when not stuffing RCX. */ 43 memset(buffer, 0, sizeof(buffer)); 44 guest_ins_port80(buffer, 8192); 45 for (i = 0; i < 8192; i++) 46 GUEST_ASSERT_2(buffer[i] == 0xaa, i, buffer[i]); 47 48 GUEST_DONE(); 49 } 50 51 int main(int argc, char *argv[]) 52 { 53 struct kvm_vcpu *vcpu; 54 struct kvm_regs regs; 55 struct kvm_run *run; 56 struct kvm_vm *vm; 57 struct ucall uc; 58 59 vm = vm_create_with_one_vcpu(&vcpu, guest_code); 60 run = vcpu->run; 61 62 memset(®s, 0, sizeof(regs)); 63 64 while (1) { 65 vcpu_run(vcpu); 66 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); 67 68 if (get_ucall(vcpu, &uc)) 69 break; 70 71 TEST_ASSERT(run->io.port == 0x80, 72 "Expected I/O at port 0x80, got port 0x%x\n", run->io.port); 73 74 /* 75 * Modify the rep string count in RCX: 2 => 1 and 3 => 8192. 76 * Note, this abuses KVM's batching of rep string I/O to avoid 77 * getting stuck in an infinite loop. That behavior isn't in 78 * scope from a testing perspective as it's not ABI in any way, 79 * i.e. it really is abusing internal KVM knowledge. 80 */ 81 vcpu_regs_get(vcpu, ®s); 82 if (regs.rcx == 2) 83 regs.rcx = 1; 84 if (regs.rcx == 3) 85 regs.rcx = 8192; 86 memset((void *)run + run->io.data_offset, 0xaa, 4096); 87 vcpu_regs_set(vcpu, ®s); 88 } 89 90 switch (uc.cmd) { 91 case UCALL_DONE: 92 break; 93 case UCALL_ABORT: 94 REPORT_GUEST_ASSERT_2(uc, "argN+1 = 0x%lx, argN+2 = 0x%lx"); 95 default: 96 TEST_FAIL("Unknown ucall %lu", uc.cmd); 97 } 98 99 kvm_vm_free(vm); 100 return 0; 101 } 102