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// SPDX-License-Identifier: GPL-2.0
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
static void guest_ins_port80(uint8_t *buffer, unsigned int count)
{
unsigned long end;
if (count == 2)
end = (unsigned long)buffer + 1;
else
end = (unsigned long)buffer + 8192;
asm volatile("cld; rep; insb" : "+D"(buffer), "+c"(count) : "d"(0x80) : "memory");
GUEST_ASSERT_EQ(count, 0);
GUEST_ASSERT_EQ((unsigned long)buffer, end);
}
static void guest_code(void)
{
uint8_t buffer[8192];
int i;
/*
* Special case tests. main() will adjust RCX 2 => 1 and 3 => 8192 to
* test that KVM doesn't explode when userspace modifies the "count" on
* a userspace I/O exit. KVM isn't required to play nice with the I/O
* itself as KVM doesn't support manipulating the count, it just needs
* to not explode or overflow a buffer.
*/
guest_ins_port80(buffer, 2);
guest_ins_port80(buffer, 3);
/* Verify KVM fills the buffer correctly when not stuffing RCX. */
memset(buffer, 0, sizeof(buffer));
guest_ins_port80(buffer, 8192);
for (i = 0; i < 8192; i++)
__GUEST_ASSERT(buffer[i] == 0xaa,
"Expected '0xaa', got '0x%x' at buffer[%u]",
buffer[i], i);
GUEST_DONE();
}
int main(int argc, char *argv[])
{
struct kvm_vcpu *vcpu;
struct kvm_regs regs;
struct kvm_run *run;
struct kvm_vm *vm;
struct ucall uc;
vm = vm_create_with_one_vcpu(&vcpu, guest_code);
run = vcpu->run;
memset(®s, 0, sizeof(regs));
while (1) {
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
if (get_ucall(vcpu, &uc))
break;
TEST_ASSERT(run->io.port == 0x80,
"Expected I/O at port 0x80, got port 0x%x", run->io.port);
/*
* Modify the rep string count in RCX: 2 => 1 and 3 => 8192.
* Note, this abuses KVM's batching of rep string I/O to avoid
* getting stuck in an infinite loop. That behavior isn't in
* scope from a testing perspective as it's not ABI in any way,
* i.e. it really is abusing internal KVM knowledge.
*/
vcpu_regs_get(vcpu, ®s);
if (regs.rcx == 2)
regs.rcx = 1;
if (regs.rcx == 3)
regs.rcx = 8192;
memset((void *)run + run->io.data_offset, 0xaa, 4096);
vcpu_regs_set(vcpu, ®s);
}
switch (uc.cmd) {
case UCALL_DONE:
break;
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
kvm_vm_free(vm);
return 0;
}
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