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_EQ(count, 0); 24 GUEST_ASSERT_EQ((unsigned long)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(buffer[i] == 0xaa, 47 "Expected '0xaa', got '0x%x' at buffer[%u]", 48 buffer[i], i); 49 50 GUEST_DONE(); 51 } 52 53 int main(int argc, char *argv[]) 54 { 55 struct kvm_vcpu *vcpu; 56 struct kvm_regs regs; 57 struct kvm_run *run; 58 struct kvm_vm *vm; 59 struct ucall uc; 60 61 vm = vm_create_with_one_vcpu(&vcpu, guest_code); 62 run = vcpu->run; 63 64 memset(®s, 0, sizeof(regs)); 65 66 while (1) { 67 vcpu_run(vcpu); 68 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO); 69 70 if (get_ucall(vcpu, &uc)) 71 break; 72 73 TEST_ASSERT(run->io.port == 0x80, 74 "Expected I/O at port 0x80, got port 0x%x", run->io.port); 75 76 /* 77 * Modify the rep string count in RCX: 2 => 1 and 3 => 8192. 78 * Note, this abuses KVM's batching of rep string I/O to avoid 79 * getting stuck in an infinite loop. That behavior isn't in 80 * scope from a testing perspective as it's not ABI in any way, 81 * i.e. it really is abusing internal KVM knowledge. 82 */ 83 vcpu_regs_get(vcpu, ®s); 84 if (regs.rcx == 2) 85 regs.rcx = 1; 86 if (regs.rcx == 3) 87 regs.rcx = 8192; 88 memset((void *)run + run->io.data_offset, 0xaa, 4096); 89 vcpu_regs_set(vcpu, ®s); 90 } 91 92 switch (uc.cmd) { 93 case UCALL_DONE: 94 break; 95 case UCALL_ABORT: 96 REPORT_GUEST_ASSERT(uc); 97 default: 98 TEST_FAIL("Unknown ucall %lu", uc.cmd); 99 } 100 101 kvm_vm_free(vm); 102 return 0; 103 } 104