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KVM: selftests: Touch relevant XSAVE state in guest for state test 

Modify support XSAVE state in the "state test's" guest code so that saving
and loading state via KVM_{G,S}ET_XSAVE actually does something useful,
i.e. so that xstate_bv in XSAVE state isn't empty.

Punt on BNDCSR for now, it's easier to just stuff that xfeature from the
host side.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230928001956.924301-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2023-09-27 17:19:54 -07:00 committed by Paolo Bonzini
parent 8647c52e95
commit 60d351f18f
2 changed files with 91 additions and 0 deletions
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14
tools/testing/selftests/kvm/include/x86_64/processor.h
View File

@ -68,6 +68,12 @@ struct xstate {
#define XFEATURE_MASK_OPMASK BIT_ULL(5)
#define XFEATURE_MASK_ZMM_Hi256 BIT_ULL(6)
#define XFEATURE_MASK_Hi16_ZMM BIT_ULL(7)
#define XFEATURE_MASK_PT BIT_ULL(8)
#define XFEATURE_MASK_PKRU BIT_ULL(9)
#define XFEATURE_MASK_PASID BIT_ULL(10)
#define XFEATURE_MASK_CET_USER BIT_ULL(11)
#define XFEATURE_MASK_CET_KERNEL BIT_ULL(12)
#define XFEATURE_MASK_LBR BIT_ULL(15)
#define XFEATURE_MASK_XTILE_CFG BIT_ULL(17)
#define XFEATURE_MASK_XTILE_DATA BIT_ULL(18)
@ -147,6 +153,7 @@ struct kvm_x86_cpu_feature {
#define X86_FEATURE_CLWB KVM_X86_CPU_FEATURE(0x7, 0, EBX, 24)
#define X86_FEATURE_UMIP KVM_X86_CPU_FEATURE(0x7, 0, ECX, 2)
#define X86_FEATURE_PKU KVM_X86_CPU_FEATURE(0x7, 0, ECX, 3)
#define X86_FEATURE_OSPKE KVM_X86_CPU_FEATURE(0x7, 0, ECX, 4)
#define X86_FEATURE_LA57 KVM_X86_CPU_FEATURE(0x7, 0, ECX, 16)
#define X86_FEATURE_RDPID KVM_X86_CPU_FEATURE(0x7, 0, ECX, 22)
#define X86_FEATURE_SGX_LC KVM_X86_CPU_FEATURE(0x7, 0, ECX, 30)
@ -553,6 +560,13 @@ static inline void xsetbv(u32 index, u64 value)
__asm__ __volatile__("xsetbv" :: "a" (eax), "d" (edx), "c" (index));
}
static inline void wrpkru(u32 pkru)
{
/* Note, ECX and EDX are architecturally required to be '0'. */
asm volatile(".byte 0x0f,0x01,0xef\n\t"
: : "a" (pkru), "c"(0), "d"(0));
}
static inline struct desc_ptr get_gdt(void)
{
struct desc_ptr gdt;

77
tools/testing/selftests/kvm/x86_64/state_test.c
View File

@ -139,6 +139,83 @@ static void vmx_l1_guest_code(struct vmx_pages *vmx_pages)
static void __attribute__((__flatten__)) guest_code(void *arg)
{
GUEST_SYNC(1);
if (this_cpu_has(X86_FEATURE_XSAVE)) {
uint64_t supported_xcr0 = this_cpu_supported_xcr0();
uint8_t buffer[4096];
memset(buffer, 0xcc, sizeof(buffer));
set_cr4(get_cr4() | X86_CR4_OSXSAVE);
GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
xsetbv(0, xgetbv(0) | supported_xcr0);
/*
* Modify state for all supported xfeatures to take them out of
* their "init" state, i.e. to make them show up in XSTATE_BV.
*
* Note off-by-default features, e.g. AMX, are out of scope for
* this particular testcase as they have a different ABI.
*/
GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_FP);
asm volatile ("fincstp");
GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_SSE);
asm volatile ("vmovdqu %0, %%xmm0" :: "m" (buffer));
if (supported_xcr0 & XFEATURE_MASK_YMM)
asm volatile ("vmovdqu %0, %%ymm0" :: "m" (buffer));
if (supported_xcr0 & XFEATURE_MASK_AVX512) {
asm volatile ("kmovq %0, %%k1" :: "r" (-1ull));
asm volatile ("vmovupd %0, %%zmm0" :: "m" (buffer));
asm volatile ("vmovupd %0, %%zmm16" :: "m" (buffer));
}
if (this_cpu_has(X86_FEATURE_MPX)) {
uint64_t bounds[2] = { 10, 0xffffffffull };
uint64_t output[2] = { };
GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDREGS);
GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_BNDCSR);
/*
* Don't bother trying to get BNDCSR into the INUSE
* state. MSR_IA32_BNDCFGS doesn't count as it isn't
* managed via XSAVE/XRSTOR, and BNDCFGU can only be
* modified by XRSTOR. Stuffing XSTATE_BV in the host
* is simpler than doing XRSTOR here in the guest.
*
* However, temporarily enable MPX in BNDCFGS so that
* BNDMOV actually loads BND1. If MPX isn't *fully*
* enabled, all MPX instructions are treated as NOPs.
*
* Hand encode "bndmov (%rax),%bnd1" as support for MPX
* mnemonics/registers has been removed from gcc and
* clang (and was never fully supported by clang).
*/
wrmsr(MSR_IA32_BNDCFGS, BIT_ULL(0));
asm volatile (".byte 0x66,0x0f,0x1a,0x08" :: "a" (bounds));
/*
* Hand encode "bndmov %bnd1, (%rax)" to sanity check
* that BND1 actually got loaded.
*/
asm volatile (".byte 0x66,0x0f,0x1b,0x08" :: "a" (output));
wrmsr(MSR_IA32_BNDCFGS, 0);
GUEST_ASSERT_EQ(bounds[0], output[0]);
GUEST_ASSERT_EQ(bounds[1], output[1]);
}
if (this_cpu_has(X86_FEATURE_PKU)) {
GUEST_ASSERT(supported_xcr0 & XFEATURE_MASK_PKRU);
set_cr4(get_cr4() | X86_CR4_PKE);
GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSPKE));
wrpkru(-1u);
}
}
GUEST_SYNC(2);
if (arg) {