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// SPDX-License-Identifier: GPL-2.0
/*
* CR4 and CPUID sync test
*
* Copyright 2018, Red Hat, Inc. and/or its affiliates.
*
* Author:
* Wei Huang <wei@redhat.com>
*/
#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"
#define MAGIC_HYPERCALL_PORT 0x80
static void guest_code(void)
{
u32 regs[4] = {
[KVM_CPUID_EAX] = X86_FEATURE_OSXSAVE.function,
[KVM_CPUID_ECX] = X86_FEATURE_OSXSAVE.index,
};
/* CR4.OSXSAVE should be enabled by default (for selftests vCPUs). */
GUEST_ASSERT(get_cr4() & X86_CR4_OSXSAVE);
/* verify CR4.OSXSAVE == CPUID.OSXSAVE */
GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
/*
* Notify hypervisor to clear CR4.0SXSAVE, do CPUID and save output,
* and then restore CR4. Do this all in assembly to ensure no AVX
* instructions are executed while OSXSAVE=0.
*/
asm volatile (
"out %%al, $" __stringify(MAGIC_HYPERCALL_PORT) "\n\t"
"cpuid\n\t"
"mov %%rdi, %%cr4\n\t"
: "+a" (regs[KVM_CPUID_EAX]),
"=b" (regs[KVM_CPUID_EBX]),
"+c" (regs[KVM_CPUID_ECX]),
"=d" (regs[KVM_CPUID_EDX])
: "D" (get_cr4())
);
/* Verify KVM cleared OSXSAVE in CPUID when it was cleared in CR4. */
GUEST_ASSERT(!(regs[X86_FEATURE_OSXSAVE.reg] & BIT(X86_FEATURE_OSXSAVE.bit)));
/* Verify restoring CR4 also restored OSXSAVE in CPUID. */
GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
GUEST_DONE();
}
int main(int argc, char *argv[])
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
struct kvm_sregs sregs;
struct ucall uc;
TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_XSAVE));
vm = vm_create_with_one_vcpu(&vcpu, guest_code);
while (1) {
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
if (vcpu->run->io.port == MAGIC_HYPERCALL_PORT &&
vcpu->run->io.direction == KVM_EXIT_IO_OUT) {
/* emulate hypervisor clearing CR4.OSXSAVE */
vcpu_sregs_get(vcpu, &sregs);
sregs.cr4 &= ~X86_CR4_OSXSAVE;
vcpu_sregs_set(vcpu, &sregs);
continue;
}
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
break;
case UCALL_DONE:
goto done;
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
}
done:
kvm_vm_free(vm);
return 0;
}
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