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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] tests: Introduce a TSX test
commit 4bcf6433eed3d9cbc00865ec62380a33ca832dac
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Jun 10 12:34:45 2021 +0100
Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Jun 15 20:50:32 2021 +0100
tests: Introduce a TSX test
See the comment at the top of test-tsx.c for details.
This covers various complexities encountered while trying to address the
recent TSX deprecation on client parts.
A sample run on KabyLake with latest microcode and default tsx= looks like
this:
root@host# ./test-tsx
TSX tests
Got 8 CPUs
Testing MSR_TSX_FORCE_ABORT consistency
CPU0 val 0x3
Testing MSR_TSX_CTRL consistency
Testing RTM behaviour
Got Abort
Testing PV default/max policies
Max: RTM 1, HLE 1, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Def: RTM 0, HLE 0, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Testing HVM default/max policies
Max: RTM 1, HLE 1, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Def: RTM 0, HLE 0, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Testing PV guest
Created d7
Cur: RTM 0, HLE 0, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Cur: RTM 1, HLE 1, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Testing HVM guest
Created d8
Cur: RTM 0, HLE 0, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Cur: RTM 1, HLE 1, TSX_FORCE_ABORT 0, RTM_ALWAYS_ABORT 0, TSX_CTRL 0
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
tools/tests/Makefile | 1 +
tools/tests/tsx/.gitignore | 1 +
tools/tests/tsx/Makefile | 45 ++++
tools/tests/tsx/test-tsx.c | 538 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 585 insertions(+)
diff --git a/tools/tests/Makefile b/tools/tests/Makefile
index 8746aabe6b..25531a984a 100644
--- a/tools/tests/Makefile
+++ b/tools/tests/Makefile
@@ -5,6 +5,7 @@ SUBDIRS-y :=
SUBDIRS-y += resource
SUBDIRS-$(CONFIG_X86) += cpu-policy
SUBDIRS-$(CONFIG_X86) += mce-test
+SUBDIRS-$(CONFIG_X86) += tsx
ifneq ($(clang),y)
SUBDIRS-$(CONFIG_X86) += x86_emulator
endif
diff --git a/tools/tests/tsx/.gitignore b/tools/tests/tsx/.gitignore
new file mode 100644
index 0000000000..97ec4db7ff
--- /dev/null
+++ b/tools/tests/tsx/.gitignore
@@ -0,0 +1 @@
+test-tsx
diff --git a/tools/tests/tsx/Makefile b/tools/tests/tsx/Makefile
new file mode 100644
index 0000000000..d7d2a5d95e
--- /dev/null
+++ b/tools/tests/tsx/Makefile
@@ -0,0 +1,45 @@
+XEN_ROOT = $(CURDIR)/../../..
+include $(XEN_ROOT)/tools/Rules.mk
+
+TARGET := test-tsx
+
+.PHONY: all
+all: $(TARGET)
+
+.PHONY: clean
+clean:
+ $(RM) -- *.o $(TARGET) $(DEPS_RM)
+
+.PHONY: distclean
+distclean: clean
+ $(RM) -- *~
+
+.PHONY: install
+install: all
+ $(INSTALL_DIR) $(DESTDIR)$(LIBEXEC_BIN)
+ $(INSTALL_PROG) $(TARGET) $(DESTDIR)$(LIBEXEC_BIN)
+
+.PHONY: uninstall
+uninstall:
+ $(RM) -- $(DESTDIR)$(LIBEXEC_BIN)/$(TARGET)
+
+.PHONY: uninstall
+uninstall:
+
+CFLAGS += -Werror
+CFLAGS += -I$(XEN_ROOT)/tools/libs/ctrl -I$(XEN_ROOT)/tools/libs/guest
+CFLAGS += $(CFLAGS_xeninclude)
+CFLAGS += $(CFLAGS_libxenctrl)
+CFLAGS += $(CFLAGS_libxenguest)
+CFLAGS += $(APPEND_CFLAGS)
+
+LDFLAGS += $(LDLIBS_libxenctrl)
+LDFLAGS += $(LDLIBS_libxenguest)
+LDFLAGS += $(APPEND_LDFLAGS)
+
+%.o: Makefile
+
+$(TARGET): test-tsx.o
+ $(CC) -o $@ $< $(LDFLAGS)
+
+-include $(DEPS_INCLUDE)
diff --git a/tools/tests/tsx/test-tsx.c b/tools/tests/tsx/test-tsx.c
new file mode 100644
index 0000000000..fab99c135e
--- /dev/null
+++ b/tools/tests/tsx/test-tsx.c
@@ -0,0 +1,538 @@
+/*
+ * TSX settings and consistency tests
+ *
+ * This tests various behaviours and invariants with regards to TSX. It
+ * ideally wants running for several microcode versions, and all applicable
+ * tsx= commandline settings, on a single CPU, including after an S3
+ * suspend/resume event.
+ *
+ * It tests specifically:
+ * - The consistency of MSR_TSX_CTRL/MSR_TSX_FORCE_ABORT values across the
+ * system, and their accessibility WRT data in the host CPU policy.
+ * - The actual behaviour of RTM on the system.
+ * - Cross-check the default/max policies based on the actual RTM behaviour.
+ * - Create some guests, check their defaults, and check that the defaults
+ * can be changed.
+ */
+
+#define _GNU_SOURCE
+
+#include <err.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/ucontext.h>
+
+#include <xenctrl.h>
+#include <xenguest.h>
+#include <xen-tools/libs.h>
+
+#include "xg_private.h"
+
+enum {
+#define XEN_CPUFEATURE(name, value) X86_FEATURE_##name = value,
+#include <xen/arch-x86/cpufeatureset.h>
+};
+#define bitmaskof(idx) (1u << ((idx) & 31))
+
+#define MSR_ARCH_CAPABILITIES 0x0000010a
+#define ARCH_CAPS_TSX_CTRL (1 << 7)
+#define MSR_TSX_FORCE_ABORT 0x0000010f
+#define MSR_TSX_CTRL 0x00000122
+
+static unsigned int nr_failures;
+#define fail(fmt, ...) \
+({ \
+ nr_failures++; \
+ (void)printf(fmt, ##__VA_ARGS__); \
+})
+
+static xc_interface *xch;
+
+/*
+ * Policies, arranged as an array for easy collection of all of them. We
+ * don't care about the raw policy (index 0) so reuse that for the guest
+ * policy.
+ */
+static struct xc_cpu_policy policies[6];
+#define guest_policy policies[0]
+#define host policies[XEN_SYSCTL_cpu_policy_host]
+#define pv_max policies[XEN_SYSCTL_cpu_policy_pv_max]
+#define hvm_max policies[XEN_SYSCTL_cpu_policy_hvm_max]
+#define pv_default policies[XEN_SYSCTL_cpu_policy_pv_default]
+#define hvm_default policies[XEN_SYSCTL_cpu_policy_hvm_default]
+
+static bool xen_has_pv = true, xen_has_hvm = true;
+
+static xc_physinfo_t physinfo;
+
+static enum rtm_behaviour {
+ RTM_UD,
+ RTM_OK,
+ RTM_ABORT,
+} rtm_behaviour;
+
+/*
+ * Test a specific TSX MSR for consistency across the system, taking into
+ * account whether it ought to be accessible or not.
+ *
+ * We can't query offline CPUs, so skip those if encountered. We don't care
+ * particularly for the exact MSR value, but we do care that it is the same
+ * everywhere.
+ */
+static void test_tsx_msr_consistency(unsigned int msr, bool accessible)
+{
+ uint64_t cpu0_val = ~0;
+
+ for ( unsigned int cpu = 0; cpu <= physinfo.max_cpu_id; ++cpu )
+ {
+ xc_resource_entry_t ent = {
+ .u.cmd = XEN_RESOURCE_OP_MSR_READ,
+ .idx = msr,
+ };
+ xc_resource_op_t op = {
+ .cpu = cpu,
+ .entries = &ent,
+ .nr_entries = 1,
+ };
+ int rc = xc_resource_op(xch, 1, &op);
+
+ if ( rc < 0 )
+ {
+ /* Don't emit a message for offline CPUs */
+ if ( errno != ENODEV )
+ fail(" xc_resource_op() for CPU%u failed: rc %d, errno %d -
%s\n",
+ cpu, rc, errno, strerror(errno));
+ continue;
+ }
+
+ if ( accessible )
+ {
+ if ( rc != 1 )
+ {
+ fail(" Expected 1 result, got %d\n", rc);
+ continue;
+ }
+ if ( ent.u.ret != 0 )
+ {
+ fail(" Expected ok, got %d\n", ent.u.ret);
+ continue;
+ }
+ }
+ else
+ {
+ if ( rc != 0 )
+ fail(" Expected 0 results, got %u\n", rc);
+ else if ( ent.u.ret != -EPERM )
+ fail(" Expected -EPERM, got %d\n", ent.u.ret);
+ continue;
+ }
+
+ if ( cpu == 0 )
+ {
+ cpu0_val = ent.val;
+ printf(" CPU0 val %#"PRIx64"\n", cpu0_val);
+ }
+ else if ( ent.val != cpu0_val )
+ fail(" CPU%u val %#"PRIx64" differs from CPU0 %#"PRIx64"\n",
+ cpu, ent.val, cpu0_val);
+ }
+}
+
+/*
+ * Check all TSX MSRs, and in particular that their accessibility matches what
+ * is expressed in the host CPU policy.
+ */
+static void test_tsx_msrs(void)
+{
+ printf("Testing MSR_TSX_FORCE_ABORT consistency\n");
+ test_tsx_msr_consistency(
+ MSR_TSX_FORCE_ABORT, host.cpuid.feat.tsx_force_abort);
+
+ printf("Testing MSR_TSX_CTRL consistency\n");
+ test_tsx_msr_consistency(
+ MSR_TSX_CTRL, host.msr.arch_caps.tsx_ctrl);
+}
+
+/*
+ * Probe for how RTM behaves, deliberately not inspecting CPUID.
+ * Distinguishes between "no support at all" (i.e. XBEGIN suffers #UD),
+ * working ok, and appearing to always abort.
+ */
+static enum rtm_behaviour probe_rtm_behaviour(void)
+{
+ for ( unsigned int i = 0; i < 1000; ++i )
+ {
+ /*
+ * Opencoding the RTM infrastructure from immintrin.h, because we
+ * still support older versions of GCC. Also so we can include #UD
+ * detection logic.
+ */
+#define XBEGIN_STARTED -1
+#define XBEGIN_UD -2
+ unsigned int status = XBEGIN_STARTED;
+
+ asm volatile ( ".Lxbegin: .byte 0xc7,0xf8,0,0,0,0" /* XBEGIN 1f; 1: */
+ : "+a" (status) :: "memory" );
+ if ( status == XBEGIN_STARTED )
+ {
+ asm volatile ( ".byte 0x0f,0x01,0xd5" ::: "memory" ); /* XEND */
+ return RTM_OK;
+ }
+ else if ( status == XBEGIN_UD )
+ return RTM_UD;
+ }
+
+ return RTM_ABORT;
+}
+
+static struct sigaction old_sigill;
+
+static void sigill_handler(int signo, siginfo_t *info, void *extra)
+{
+ extern const char xbegin_label[] asm(".Lxbegin");
+
+ if ( info->si_addr == xbegin_label &&
+ memcmp(info->si_addr, "\xc7\xf8\x00\x00\x00\x00", 6) == 0 )
+ {
+ ucontext_t *context = extra;
+
+ /*
+ * Found the XBEGIN instruction. Step over it, and update `status` to
+ * signal #UD.
+ */
+#if defined(__linux__)
+# ifdef __x86_64__
+ context->uc_mcontext.gregs[REG_RIP] += 6;
+ context->uc_mcontext.gregs[REG_RAX] = XBEGIN_UD;
+# else
+ context->uc_mcontext.gregs[REG_EIP] += 6;
+ context->uc_mcontext.gregs[REG_EAX] = XBEGIN_UD;
+# endif
+
+#elif defined(__FreeBSD__)
+# ifdef __x86_64__
+ context->uc_mcontext.mc_rip += 6;
+ context->uc_mcontext.mc_rax = XBEGIN_UD;
+# else
+ context->uc_mcontext.mc_eip += 6;
+ context->uc_mcontext.mc_eax = XBEGIN_UD;
+# endif
+
+#elif defined(__NetBSD__)
+# ifdef __x86_64__
+ context->uc_mcontext.__gregs[_REG_RIP] += 6;
+ context->uc_mcontext.__gregs[_REG_RAX] = XBEGIN_UD;
+# else
+ context->uc_mcontext.__gregs[_REG_EIP] += 6;
+ context->uc_mcontext.__gregs[_REG_EAX] = XBEGIN_UD;
+# endif
+
+#else
+# error Unknown environment - please adjust
+#endif
+ }
+ else
+ {
+ /*
+ * Not the SIGILL we're looking for... Restore the old handler and
+ * try again. Will likely coredump as a result.
+ */
+ sigaction(SIGILL, &old_sigill, NULL);
+ }
+}
+
+static void test_rtm_behaviour(void)
+{
+ struct sigaction new_sigill = {
+ .sa_flags = SA_SIGINFO,
+ .sa_sigaction = sigill_handler,
+ };
+ const char *str;
+
+ printf("Testing RTM behaviour\n");
+
+ /*
+ * Install a custom SIGILL handler while probing for RTM behaviour, as the
+ * XBEGIN instruction might suffer #UD.
+ */
+ sigaction(SIGILL, &new_sigill, &old_sigill);
+ rtm_behaviour = probe_rtm_behaviour();
+ sigaction(SIGILL, &old_sigill, NULL);
+
+ switch ( rtm_behaviour )
+ {
+ case RTM_UD: str = "#UD"; break;
+ case RTM_OK: str = "OK"; break;
+ case RTM_ABORT: str = "Abort"; break;
+ default: str = NULL; break;
+ }
+
+ if ( str )
+ printf(" Got %s\n", str);
+ else
+ return fail(" Got unexpected behaviour %d\n", rtm_behaviour);
+
+ if ( host.cpuid.feat.rtm )
+ {
+ if ( rtm_behaviour == RTM_UD )
+ fail(" Host reports RTM, but appears unavailable\n");
+ }
+ else
+ {
+ if ( rtm_behaviour != RTM_UD )
+ fail(" Host reports no RTM, but appears available\n");
+ }
+}
+
+static void dump_tsx_details(const struct xc_cpu_policy *p, const char *pref)
+{
+ printf(" %s RTM %u, HLE %u, TSX_FORCE_ABORT %u, RTM_ALWAYS_ABORT %u,
TSX_CTRL %u\n",
+ pref,
+ p->cpuid.feat.rtm,
+ p->cpuid.feat.hle,
+ p->cpuid.feat.tsx_force_abort,
+ p->cpuid.feat.rtm_always_abort,
+ p->msr.arch_caps.tsx_ctrl);
+}
+
+/* Sanity test various invariants we expect in the default/max policies. */
+static void test_guest_policies(const struct xc_cpu_policy *max,
+ const struct xc_cpu_policy *def)
+{
+ const struct cpuid_policy *cm = &max->cpuid;
+ const struct cpuid_policy *cd = &def->cpuid;
+ const struct msr_policy *mm = &max->msr;
+ const struct msr_policy *md = &def->msr;
+
+ dump_tsx_details(max, "Max:");
+ dump_tsx_details(def, "Def:");
+
+ if ( ((cm->feat.raw[0].d | cd->feat.raw[0].d) &
+ (bitmaskof(X86_FEATURE_TSX_FORCE_ABORT) |
+ bitmaskof(X86_FEATURE_RTM_ALWAYS_ABORT))) ||
+ ((mm->arch_caps.raw | md->arch_caps.raw) & ARCH_CAPS_TSX_CTRL) )
+ fail(" Xen-only TSX controls offered to guest\n");
+
+ switch ( rtm_behaviour )
+ {
+ case RTM_UD:
+ if ( (cm->feat.raw[0].b | cd->feat.raw[0].b) &
+ (bitmaskof(X86_FEATURE_HLE) | bitmaskof(X86_FEATURE_RTM)) )
+ fail(" HLE/RTM offered to guests despite not being available\n");
+ break;
+
+ case RTM_ABORT:
+ if ( cd->feat.raw[0].b &
+ (bitmaskof(X86_FEATURE_HLE) | bitmaskof(X86_FEATURE_RTM)) )
+ fail(" HLE/RTM offered to guests by default despite not being
usable\n");
+ break;
+
+ case RTM_OK:
+ if ( !cm->feat.rtm || !cd->feat.rtm )
+ fail(" RTM not offered to guests despite being available\n");
+ break;
+ }
+
+ if ( cd->feat.hle )
+ fail(" Fail: HLE offered in default policy\n");
+}
+
+static void test_def_max_policies(void)
+{
+ if ( xen_has_pv )
+ {
+ printf("Testing PV default/max policies\n");
+ test_guest_policies(&pv_max, &pv_default);
+ }
+
+ if ( xen_has_hvm )
+ {
+ printf("Testing HVM default/max policies\n");
+ test_guest_policies(&hvm_max, &hvm_default);
+ }
+}
+
+static void test_guest(struct xen_domctl_createdomain *c)
+{
+ uint32_t domid = 0;
+ int rc;
+
+ rc = xc_domain_create(xch, &domid, c);
+ if ( rc )
+ return fail(" Domain create failure: %d - %s\n",
+ errno, strerror(errno));
+
+ printf(" Created d%u\n", domid);
+
+ rc = xc_cpu_policy_get_domain(xch, domid, &guest_policy);
+ if ( rc )
+ {
+ fail(" Failed to obtain domain policy: %d - %s\n",
+ errno, strerror(errno));
+ goto out;
+ }
+
+ dump_tsx_details(&guest_policy, "Cur:");
+
+ /*
+ * Check defaults given to the guest.
+ */
+ if ( guest_policy.cpuid.feat.rtm != (rtm_behaviour == RTM_OK) )
+ fail(" RTM %u in guest, despite rtm behaviour\n",
+ guest_policy.cpuid.feat.rtm);
+
+ if ( guest_policy.cpuid.feat.hle ||
+ guest_policy.cpuid.feat.tsx_force_abort ||
+ guest_policy.cpuid.feat.rtm_always_abort ||
+ guest_policy.msr.arch_caps.tsx_ctrl )
+ fail(" Unexpected features advertised\n");
+
+ if ( host.cpuid.feat.rtm )
+ {
+ unsigned int _7b0;
+
+ /*
+ * If host RTM is available, all combinations of guest flags should be
+ * possible. Flip both HLE/RTM to check non-default settings.
+ */
+ _7b0 = (guest_policy.cpuid.feat.raw[0].b ^=
+ (bitmaskof(X86_FEATURE_HLE) | bitmaskof(X86_FEATURE_RTM)));
+
+ /* Set the new policy. */
+ rc = xc_cpu_policy_set_domain(xch, domid, &guest_policy);
+ if ( rc )
+ {
+ fail(" Failed to set domain policy: %d - %s\n",
+ errno, strerror(errno));
+ goto out;
+ }
+
+ /* Re-get the new policy. */
+ rc = xc_cpu_policy_get_domain(xch, domid, &guest_policy);
+ if ( rc )
+ {
+ fail(" Failed to obtain domain policy: %d - %s\n",
+ errno, strerror(errno));
+ goto out;
+ }
+
+ dump_tsx_details(&guest_policy, "Cur:");
+
+ if ( guest_policy.cpuid.feat.raw[0].b != _7b0 )
+ {
+ fail(" Expected CPUID.7[1].b 0x%08x differs from actual 0x%08x\n",
+ _7b0, guest_policy.cpuid.feat.raw[0].b);
+ goto out;
+ }
+ }
+
+ out:
+ rc = xc_domain_destroy(xch, domid);
+ if ( rc )
+ fail(" Failed to destroy domain: %d - %s\n",
+ errno, strerror(errno));
+}
+
+static void test_guests(void)
+{
+ if ( xen_has_pv )
+ {
+ struct xen_domctl_createdomain c = {
+ .max_vcpus = 1,
+ .max_grant_frames = 1,
+ };
+
+ printf("Testing PV guest\n");
+ test_guest(&c);
+ }
+
+ if ( xen_has_hvm )
+ {
+ struct xen_domctl_createdomain c = {
+ .flags = XEN_DOMCTL_CDF_hvm,
+ .max_vcpus = 1,
+ .max_grant_frames = 1,
+ .arch = {
+ .emulation_flags = XEN_X86_EMU_LAPIC,
+ },
+ };
+
+ if ( physinfo.capabilities & XEN_SYSCTL_PHYSCAP_hap )
+ c.flags |= XEN_DOMCTL_CDF_hap;
+ else if ( !(physinfo.capabilities & XEN_SYSCTL_PHYSCAP_shadow) )
+ return fail(" HVM available, but neither HAP nor Shadow\n");
+
+ printf("Testing HVM guest\n");
+ test_guest(&c);
+ }
+}
+
+/* Obtain some general data, then run the tests. */
+static void test_tsx(void)
+{
+ int rc;
+
+ /* Read all policies except raw. */
+ for ( unsigned int i = XEN_SYSCTL_cpu_policy_host;
+ i <= XEN_SYSCTL_cpu_policy_hvm_default; ++i )
+ {
+ rc = xc_cpu_policy_get_system(xch, i, &policies[i]);
+
+ if ( rc == -1 && errno == EOPNOTSUPP )
+ {
+ /*
+ * Use EOPNOTSUPP to spot Xen missing CONFIG_{PV,HVM}, and adjust
+ * later testing accordingly.
+ */
+ switch ( i )
+ {
+ case XEN_SYSCTL_cpu_policy_pv_max:
+ case XEN_SYSCTL_cpu_policy_pv_default:
+ if ( xen_has_pv )
+ printf(" Xen doesn't support PV\n");
+ xen_has_pv = false;
+ continue;
+
+ case XEN_SYSCTL_cpu_policy_hvm_max:
+ case XEN_SYSCTL_cpu_policy_hvm_default:
+ if ( xen_has_hvm )
+ printf(" Xen doesn't support HVM\n");
+ xen_has_hvm = false;
+ continue;
+ }
+ }
+ if ( rc )
+ return fail("Failed to obtain policy[%u]: %d - %s\n",
+ i, errno, strerror(errno));
+ }
+
+ rc = xc_physinfo(xch, &physinfo);
+ if ( rc )
+ return fail("Failed to obtain physinfo: %d - %s\n",
+ errno, strerror(errno));
+
+ printf(" Got %u CPUs\n", physinfo.max_cpu_id + 1);
+
+ test_tsx_msrs();
+ test_rtm_behaviour();
+ test_def_max_policies();
+ test_guests();
+}
+
+int main(int argc, char **argv)
+{
+ printf("TSX tests\n");
+
+ xch = xc_interface_open(NULL, NULL, 0);
+
+ if ( !xch )
+ err(1, "xc_interface_open");
+
+ test_tsx();
+
+ return !!nr_failures;
+}
--
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