diff mbox series

[3/3] selftest: Support amx selftest

Message ID 20211221231507.2910889-4-yang.zhong@intel.com (mailing list archive)
State New, archived
Headers show
Series AMX KVM selftest | expand

Commit Message

Yang Zhong Dec. 21, 2021, 11:15 p.m. UTC
This selftest do two test cases, one is to trigger #NM
exception and check MSR XFD_ERR value. Another case is
guest load tile data into tmm0 registers and trap to host
side to check memory data after save/restore.

Signed-off-by: Yang Zhong <yang.zhong@intel.com>
---
 tools/testing/selftests/kvm/Makefile          |   1 +
 tools/testing/selftests/kvm/x86_64/amx_test.c | 370 ++++++++++++++++++
 2 files changed, 371 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/amx_test.c

Comments

Paolo Bonzini Dec. 21, 2021, 5:36 p.m. UTC | #1
On 12/22/21 00:15, Yang Zhong wrote:
> This selftest do two test cases, one is to trigger #NM
> exception and check MSR XFD_ERR value. Another case is
> guest load tile data into tmm0 registers and trap to host
> side to check memory data after save/restore.
> 
> Signed-off-by: Yang Zhong <yang.zhong@intel.com>

This is a great start, mainly I'd add a lot more GUEST_SYNCs.

Basically any instruction after the initial GUEST_ASSERTs are a 
potential point for GUEST_SYNC, except right after the call to set_tilecfg:

GUEST_SYNC(1)

> +	/* xfd=0, enable amx */
> +	wrmsr(MSR_IA32_XFD, 0);

GUEST_SYNC(2)

> +	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == 0);
> +	set_tilecfg(amx_cfg);
> +	__ldtilecfg(amx_cfg);

GUEST_SYNC(3)

> +	/* Check save/restore when trap to userspace */
> +	__tileloadd(tiledata);
> +	GUEST_SYNC(1);

This would become 4; here add tilerelease+GUEST_SYNC(5)+XSAVEC, and 
check that state 18 is not included in XCOMP_BV.

> +	/* xfd=0x40000, disable amx tiledata */
> +	wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);

GUEST_SYNC(6)

> +	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == XFEATURE_MASK_XTILEDATA);
> +	set_tilecfg(amx_cfg);
> +	__ldtilecfg(amx_cfg);
> +	/* Trigger #NM exception */
> +	__tileloadd(tiledata);

GUEST_SYNC(10); this final GUEST_SYNC should also check TMM0 in the host.

> +	GUEST_DONE();
> +}
> +
> +void guest_nm_handler(struct ex_regs *regs)
> +{
> +	/* Check if #NM is triggered by XFEATURE_MASK_XTILEDATA */

GUEST_SYNC(7)

> +	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);
> +	/* Clear xfd_err */

Same here, I'd do a GUEST_SYNC(8) and re-read MSR_IA32_XFD_ERR.

> +	wrmsr(MSR_IA32_XFD_ERR, 0);
> +	GUEST_SYNC(2);

This becomes GUEST_SYNC(9).

> +}


> +		case UCALL_SYNC:
> +			switch (uc.args[1]) {
> +			case 1:
> +				fprintf(stderr,
> +					"Exit VM by GUEST_SYNC(1), check save/restore.\n");
> +
> +				/* Compacted mode, get amx offset by xsave area
> +				 * size subtract 8K amx size.
> +				 */
> +				amx_offset = xsave_restore_size - NUM_TILES*TILE_SIZE;
> +				state = vcpu_save_state(vm, VCPU_ID);
> +				void *amx_start = (void *)state->xsave + amx_offset;
> +				void *tiles_data = (void *)addr_gva2hva(vm, tiledata);
> +				/* Only check TMM0 register, 1 tile */
> +				ret = memcmp(amx_start, tiles_data, TILE_SIZE);
> +				TEST_ASSERT(ret == 0, "memcmp failed, ret=%d\n", ret);
> +				kvm_x86_state_cleanup(state);
> +				break;

All GUEST_SYNCs should do save_state/load_state like state_test.c.  Then 
of course you can *also* check TMM0 after __tileloadd, which would be 
cases 4 and 10.

Thanks,

Paolo

> +			case 2:
> +				fprintf(stderr,
> +					"Exit VM by GUEST_SYNC(2), generate #NM exception.\n");
> +				goto done;
> +			}
> +			break;
> +		case UCALL_DONE:
> +			goto done;
> +		default:
> +			TEST_FAIL("Unknown ucall %lu", uc.cmd);
> +		}
> +	}
> +done:
> +	kvm_vm_free(vm);
> +}
>
Yang Zhong Dec. 22, 2021, 9:02 a.m. UTC | #2
On Tue, Dec 21, 2021 at 06:36:17PM +0100, Paolo Bonzini wrote:
> On 12/22/21 00:15, Yang Zhong wrote:
> >This selftest do two test cases, one is to trigger #NM
> >exception and check MSR XFD_ERR value. Another case is
> >guest load tile data into tmm0 registers and trap to host
> >side to check memory data after save/restore.
> >
> >Signed-off-by: Yang Zhong <yang.zhong@intel.com>
> 
> This is a great start, mainly I'd add a lot more GUEST_SYNCs.
> 
> Basically any instruction after the initial GUEST_ASSERTs are a
> potential point for GUEST_SYNC, except right after the call to
> set_tilecfg:
> 
> GUEST_SYNC(1)
> 
> >+	/* xfd=0, enable amx */
> >+	wrmsr(MSR_IA32_XFD, 0);
> 
> GUEST_SYNC(2)
> 
> >+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == 0);
> >+	set_tilecfg(amx_cfg);
> >+	__ldtilecfg(amx_cfg);
> 
> GUEST_SYNC(3)
 
   Paolo, with this GUEST_SYNC(3) between __ldtilecfg and __tileloadd
   instructions, the guest code generate (vector:0x6, Invalid Opcode) 
   exception, which is a strange issue. thanks!

   Yang   


> 
> >+	/* Check save/restore when trap to userspace */
> >+	__tileloadd(tiledata);
> >+	GUEST_SYNC(1);
> 
> This would become 4; here add tilerelease+GUEST_SYNC(5)+XSAVEC, and
> check that state 18 is not included in XCOMP_BV.
>
     
   Thanks Paolo, the new code like below:

    GUEST_SYNC(5);
    /* bit 18 not in the XCOMP_BV after xsavec() */
    set_xstatebv(xsave_data, XFEATURE_MASK_XTILEDATA);
     __xsavec(xsave_data, XFEATURE_MASK_XTILEDATA);
    GUEST_ASSERT((get_xstatebv(xsave_data) & XFEATURE_MASK_XTILEDATA) == 0)


    Yang

 
> >+	/* xfd=0x40000, disable amx tiledata */
> >+	wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);
> 
> GUEST_SYNC(6)
> 
> >+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == XFEATURE_MASK_XTILEDATA);
> >+	set_tilecfg(amx_cfg);
> >+	__ldtilecfg(amx_cfg);
> >+	/* Trigger #NM exception */
> >+	__tileloadd(tiledata);
> 
> GUEST_SYNC(10); this final GUEST_SYNC should also check TMM0 in the host.
> 
> >+	GUEST_DONE();
> >+}
> >+
> >+void guest_nm_handler(struct ex_regs *regs)
> >+{
> >+	/* Check if #NM is triggered by XFEATURE_MASK_XTILEDATA */
> 
> GUEST_SYNC(7)
> 
> >+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);
> >+	/* Clear xfd_err */
> 
> Same here, I'd do a GUEST_SYNC(8) and re-read MSR_IA32_XFD_ERR.
> 
> >+	wrmsr(MSR_IA32_XFD_ERR, 0);
> >+	GUEST_SYNC(2);
> 
   
    This need add regs->rip +=3 to skip __tileloadd() instruction(generate #NM) 
    when VM resume from GUEST_SYNC(9).

    Thanks!

    Yang


> This becomes GUEST_SYNC(9).
> 
> >+}
> 
> 
> >+		case UCALL_SYNC:
> >+			switch (uc.args[1]) {
> >+			case 1:
> >+				fprintf(stderr,
> >+					"Exit VM by GUEST_SYNC(1), check save/restore.\n");
> >+
> >+				/* Compacted mode, get amx offset by xsave area
> >+				 * size subtract 8K amx size.
> >+				 */
> >+				amx_offset = xsave_restore_size - NUM_TILES*TILE_SIZE;
> >+				state = vcpu_save_state(vm, VCPU_ID);
> >+				void *amx_start = (void *)state->xsave + amx_offset;
> >+				void *tiles_data = (void *)addr_gva2hva(vm, tiledata);
> >+				/* Only check TMM0 register, 1 tile */
> >+				ret = memcmp(amx_start, tiles_data, TILE_SIZE);
> >+				TEST_ASSERT(ret == 0, "memcmp failed, ret=%d\n", ret);
> >+				kvm_x86_state_cleanup(state);
> >+				break;
> 
> All GUEST_SYNCs should do save_state/load_state like state_test.c.
> Then of course you can *also* check TMM0 after __tileloadd, which
> would be cases 4 and 10.
> 

  Yes, the new code will add save_state/load_state as in the state_test.c file.

  Thanks!

  Yang



> Thanks,
> 
> Paolo
> 
> >+			case 2:
> >+				fprintf(stderr,
> >+					"Exit VM by GUEST_SYNC(2), generate #NM exception.\n");
> >+				goto done;
> >+			}
> >+			break;
> >+		case UCALL_DONE:
> >+			goto done;
> >+		default:
> >+			TEST_FAIL("Unknown ucall %lu", uc.cmd);
> >+		}
> >+	}
> >+done:
> >+	kvm_vm_free(vm);
> >+}
> >
diff mbox series

Patch

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index c4e34717826a..ecb1fe022111 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -75,6 +75,7 @@  TEST_GEN_PROGS_x86_64 += x86_64/xen_shinfo_test
 TEST_GEN_PROGS_x86_64 += x86_64/xen_vmcall_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_pi_mmio_test
 TEST_GEN_PROGS_x86_64 += x86_64/sev_migrate_tests
+TEST_GEN_PROGS_x86_64 += x86_64/amx_test
 TEST_GEN_PROGS_x86_64 += demand_paging_test
 TEST_GEN_PROGS_x86_64 += dirty_log_test
 TEST_GEN_PROGS_x86_64 += dirty_log_perf_test
diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
new file mode 100644
index 000000000000..76ae44622923
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -0,0 +1,370 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * amx tests
+ *
+ * Copyright (C) 2021, Intel, Inc.
+ *
+ * Tests for amx #NM exception and save/restore.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "vmx.h"
+
+#ifndef __x86_64__
+# error This test is 64-bit only
+#endif
+
+#define VCPU_ID				0
+#define X86_FEATURE_XSAVE		(1 << 26)
+#define X86_FEATURE_OSXSAVE		(1 << 27)
+
+#define PAGE_SIZE			(1 << 12)
+#define NUM_TILES			8
+#define TILE_SIZE			1024
+#define XSAVE_SIZE			((NUM_TILES * TILE_SIZE) + PAGE_SIZE)
+
+/* Tile configuration associated: */
+#define MAX_TILES			16
+#define RESERVED_BYTES			14
+
+#define XFEATURE_XTILECFG		17
+#define XFEATURE_XTILEDATA		18
+#define XFEATURE_MASK_XTILECFG		(1 << XFEATURE_XTILECFG)
+#define XFEATURE_MASK_XTILEDATA		(1 << XFEATURE_XTILEDATA)
+#define XFEATURE_MASK_XTILE		(XFEATURE_MASK_XTILECFG | XFEATURE_MASK_XTILEDATA)
+
+#define TILE_CPUID			0x1d
+#define XSTATE_CPUID			0xd
+#define TILE_PALETTE_CPUID_SUBLEAVE	0x1
+#define XSTATE_USER_STATE_SUBLEAVE	0x0
+
+struct tile_config {
+	u8  palette_id;
+	u8  start_row;
+	u8  reserved[RESERVED_BYTES];
+	u16 colsb[MAX_TILES];
+	u8  rows[MAX_TILES];
+};
+
+struct tile_data {
+	u8 data[NUM_TILES * TILE_SIZE];
+};
+
+struct xtile_info {
+	u16 bytes_per_tile;
+	u16 bytes_per_row;
+	u16 max_names;
+	u16 max_rows;
+	u32 xsave_offset;
+	u32 xsave_size;
+};
+
+static struct xtile_info xtile;
+
+static inline u64 __xgetbv(u32 index)
+{
+	u32 eax, edx;
+
+	asm volatile("xgetbv;"
+		     : "=a" (eax), "=d" (edx)
+		     : "c" (index));
+	return eax + ((u64)edx << 32);
+}
+
+static inline void __xsetbv(u32 index, u64 value)
+{
+	u32 eax = value;
+	u32 edx = value >> 32;
+
+	asm volatile("xsetbv" :: "a" (eax), "d" (edx), "c" (index));
+}
+
+static inline void __ldtilecfg(void *cfg)
+{
+	asm volatile(".byte 0xc4,0xe2,0x78,0x49,0x00"
+		     : : "a"(cfg));
+}
+
+static inline void __tileloadd(void *tile)
+{
+	asm volatile(".byte 0xc4,0xe2,0x7b,0x4b,0x04,0x10"
+		     : : "a"(tile), "d"(0));
+}
+
+static inline void __tilerelease(void)
+{
+	asm volatile(".byte 0xc4, 0xe2, 0x78, 0x49, 0xc0" ::);
+}
+
+static inline void check_cpuid_xsave(void)
+{
+	uint32_t eax, ebx, ecx, edx;
+
+	eax = 1;
+	ecx = 0;
+	cpuid(&eax, &ebx, &ecx, &edx);
+	if (!(ecx & X86_FEATURE_XSAVE))
+		GUEST_ASSERT(!"cpuid: no CPU xsave support!");
+	if (!(ecx & X86_FEATURE_OSXSAVE))
+		GUEST_ASSERT(!"cpuid: no OS xsave support!");
+}
+
+static bool check_xsave_supports_xtile(void)
+{
+	return __xgetbv(0) & XFEATURE_MASK_XTILE;
+}
+
+static bool enum_xtile_config(void)
+{
+	u32 eax, ebx, ecx, edx;
+
+	eax = TILE_CPUID;
+	ecx = TILE_PALETTE_CPUID_SUBLEAVE;
+
+	cpuid(&eax, &ebx, &ecx, &edx);
+	if (!eax || !ebx || !ecx)
+		return false;
+
+	xtile.max_names = ebx >> 16;
+	if (xtile.max_names < NUM_TILES)
+		return false;
+
+	xtile.bytes_per_tile = eax >> 16;
+	if (xtile.bytes_per_tile < TILE_SIZE)
+		return false;
+
+	xtile.bytes_per_row = ebx;
+	xtile.max_rows = ecx;
+
+	return true;
+}
+
+static bool enum_xsave_tile(void)
+{
+	u32 eax, ebx, ecx, edx;
+
+	eax = XSTATE_CPUID;
+	ecx = XFEATURE_XTILEDATA;
+
+	cpuid(&eax, &ebx, &ecx, &edx);
+	if (!eax || !ebx)
+		return false;
+
+	xtile.xsave_offset = ebx;
+	xtile.xsave_size = eax;
+
+	return true;
+}
+
+static bool check_xsave_size(void)
+{
+	u32 eax, ebx, ecx, edx;
+	bool valid = false;
+
+	eax = XSTATE_CPUID;
+	ecx = XSTATE_USER_STATE_SUBLEAVE;
+
+	cpuid(&eax, &ebx, &ecx, &edx);
+	if (ebx && ebx <= XSAVE_SIZE)
+		valid = true;
+
+	return valid;
+}
+
+static bool check_xtile_info(void)
+{
+	bool ret = false;
+
+	if (!check_xsave_size())
+		return ret;
+
+	if (!enum_xsave_tile())
+		return ret;
+
+	if (!enum_xtile_config())
+		return ret;
+
+	if (sizeof(struct tile_data) >= xtile.xsave_size)
+		ret = true;
+
+	return ret;
+}
+
+static void set_tilecfg(struct tile_config *cfg)
+{
+	int i;
+
+	/* Only palette id 1 */
+	cfg->palette_id = 1;
+	for (i = 0; i < xtile.max_names; i++) {
+		cfg->colsb[i] = xtile.bytes_per_row;
+		cfg->rows[i] = xtile.max_rows;
+	}
+}
+
+static void init_regs(void)
+{
+	uint64_t cr4, xcr0;
+
+	/* turn on CR4.OSXSAVE */
+	cr4 = get_cr4();
+	cr4 |= X86_CR4_OSXSAVE;
+	set_cr4(cr4);
+
+	xcr0 = __xgetbv(0);
+	xcr0 |= XFEATURE_MASK_XTILE;
+	__xsetbv(0x0, xcr0);
+}
+
+static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
+						    struct tile_data *tiledata)
+{
+	init_regs();
+	check_cpuid_xsave();
+	GUEST_ASSERT(check_xsave_supports_xtile());
+	GUEST_ASSERT(check_xtile_info());
+
+	/* check xtile configs */
+	GUEST_ASSERT(xtile.xsave_offset == 2816);
+	GUEST_ASSERT(xtile.xsave_size == 8192);
+	GUEST_ASSERT(xtile.max_names == 8);
+	GUEST_ASSERT(xtile.bytes_per_tile == 1024);
+	GUEST_ASSERT(xtile.bytes_per_row == 64);
+	GUEST_ASSERT(xtile.max_rows == 16);
+
+	/* xfd=0, enable amx */
+	wrmsr(MSR_IA32_XFD, 0);
+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == 0);
+	set_tilecfg(amx_cfg);
+	__ldtilecfg(amx_cfg);
+	/* Check save/restore when trap to userspace */
+	__tileloadd(tiledata);
+	GUEST_SYNC(1);
+
+	/* xfd=0x40000, disable amx tiledata */
+	wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);
+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == XFEATURE_MASK_XTILEDATA);
+	set_tilecfg(amx_cfg);
+	__ldtilecfg(amx_cfg);
+	/* Trigger #NM exception */
+	__tileloadd(tiledata);
+
+	GUEST_DONE();
+}
+
+void guest_nm_handler(struct ex_regs *regs)
+{
+	/* Check if #NM is triggered by XFEATURE_MASK_XTILEDATA */
+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);
+	/* Clear xfd_err */
+	wrmsr(MSR_IA32_XFD_ERR, 0);
+	GUEST_SYNC(2);
+}
+
+int main(int argc, char *argv[])
+{
+	struct kvm_cpuid_entry2 *entry;
+	struct kvm_regs regs1;
+	bool amx_supported = false;
+	struct kvm_vm *vm;
+	struct kvm_run *run;
+	struct kvm_x86_state *state;
+	int xsave_restore_size = 0;
+	vm_vaddr_t amx_cfg, tiledata;
+	struct ucall uc;
+	u32 amx_offset;
+	int stage, ret;
+
+	/* Create VM */
+	vm = vm_create_default(VCPU_ID, 0, guest_code);
+
+	entry = kvm_get_supported_cpuid_entry(1);
+	if (!(entry->ecx & X86_FEATURE_XSAVE)) {
+		print_skip("XSAVE feature not supported");
+		return 0;
+	}
+
+	if (kvm_get_cpuid_max_basic() >= 0xd) {
+		entry = kvm_get_supported_cpuid_index(0xd, 0);
+		amx_supported = entry && !!(entry->eax & XFEATURE_MASK_XTILE);
+		if (!amx_supported) {
+			print_skip("AMX is not supported by the vCPU and eax=0x%x", entry->eax);
+			return 0;
+		}
+		/* Get xsave/restore max size */
+		xsave_restore_size = entry->ecx;
+	}
+
+	run = vcpu_state(vm, VCPU_ID);
+	vcpu_regs_get(vm, VCPU_ID, &regs1);
+
+	/* Register #NM handler */
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vm, VCPU_ID);
+	vm_install_exception_handler(vm, NM_VECTOR, guest_nm_handler);
+
+	/* amx cfg for guest_code */
+	amx_cfg = vm_vaddr_alloc_page(vm);
+	memset(addr_gva2hva(vm, amx_cfg), 0x0, getpagesize());
+
+	/* amx tiledatas for guest_code */
+	tiledata = vm_vaddr_alloc_pages(vm, 2);
+	memset(addr_gva2hva(vm, tiledata), rand() | 1, 2 * getpagesize());
+	vcpu_args_set(vm, VCPU_ID, 2, amx_cfg, tiledata);
+
+	for (stage = 1; ; stage++) {
+		_vcpu_run(vm, VCPU_ID);
+		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+			    "Stage %d: unexpected exit reason: %u (%s),\n",
+			    stage, run->exit_reason,
+			    exit_reason_str(run->exit_reason));
+
+		switch (get_ucall(vm, VCPU_ID, &uc)) {
+		case UCALL_ABORT:
+			TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
+				  __FILE__, uc.args[1]);
+			/* NOT REACHED */
+		case UCALL_SYNC:
+			switch (uc.args[1]) {
+			case 1:
+				fprintf(stderr,
+					"Exit VM by GUEST_SYNC(1), check save/restore.\n");
+
+				/* Compacted mode, get amx offset by xsave area
+				 * size subtract 8K amx size.
+				 */
+				amx_offset = xsave_restore_size - NUM_TILES*TILE_SIZE;
+				state = vcpu_save_state(vm, VCPU_ID);
+				void *amx_start = (void *)state->xsave + amx_offset;
+				void *tiles_data = (void *)addr_gva2hva(vm, tiledata);
+				/* Only check TMM0 register, 1 tile */
+				ret = memcmp(amx_start, tiles_data, TILE_SIZE);
+				TEST_ASSERT(ret == 0, "memcmp failed, ret=%d\n", ret);
+				kvm_x86_state_cleanup(state);
+				break;
+			case 2:
+				fprintf(stderr,
+					"Exit VM by GUEST_SYNC(2), generate #NM exception.\n");
+				goto done;
+			}
+			break;
+		case UCALL_DONE:
+			goto done;
+		default:
+			TEST_FAIL("Unknown ucall %lu", uc.cmd);
+		}
+	}
+done:
+	kvm_vm_free(vm);
+}