06ba5dd4d1
qemu-testsuite wasn't building due to null pointers in the new migration warning patch. OBS-URL: https://build.opensuse.org/request/show/579226 OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=394
76 lines
2.7 KiB
Diff
76 lines
2.7 KiB
Diff
From 555715ac88c361e4c9b262235010c265729738bf Mon Sep 17 00:00:00 2001
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From: Bruce Rogers <brogers@suse.com>
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Date: Wed, 21 Feb 2018 14:00:52 -0700
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Subject: [PATCH] migration: warn about inconsistent spec_ctrl state
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As an attempt to help the user do the right thing, warn if we
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detect spec_ctrl data in the migration stream, but where the
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cpu defined doesn't have the feature. This would indicate the
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migration is from the quick and dirty qemu produced in January
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2018 to handle Spectre v2. That qemu version exposed the IBRS
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cpu feature to all vcpu types, which helped in the short term
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but wasn't a well designed approach.
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Warn the user that the now migrated guest needs to be restarted
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as soon as possible, using the spec_ctrl cpu feature flag or a
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*-IBRS vcpu model specified as appropriate.
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Signed-off-by: Bruce Rogers <brogers@suse.com>
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---
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cpus.c | 12 ++++++++++++
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include/qemu/thread.h | 1 +
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migration/migration.c | 8 ++++++++
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3 files changed, 21 insertions(+)
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diff --git a/cpus.c b/cpus.c
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index d1e7e28993..1bfdb155dc 100644
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--- a/cpus.c
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+++ b/cpus.c
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@@ -2039,6 +2039,18 @@ exit:
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fclose(f);
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}
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+bool spec_ctrl_is_inconsistent(void)
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+{
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+#if defined(TARGET_I386)
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+ X86CPU *x86_cpu = X86_CPU(current_cpu);
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+ CPUX86State *env = x86_cpu != NULL ? &x86_cpu->env : NULL;
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+ if (env && !(env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_SPEC_CTRL) &&
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+ env->spec_ctrl)
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+ return true;
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+#endif
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+ return false;
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+}
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+
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void qmp_inject_nmi(Error **errp)
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{
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nmi_monitor_handle(monitor_get_cpu_index(), errp);
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diff --git a/include/qemu/thread.h b/include/qemu/thread.h
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index 9910f49b3a..c5803bfacc 100644
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--- a/include/qemu/thread.h
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+++ b/include/qemu/thread.h
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@@ -210,4 +210,5 @@ void qemu_lockcnt_inc_and_unlock(QemuLockCnt *lockcnt);
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*/
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unsigned qemu_lockcnt_count(QemuLockCnt *lockcnt);
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+bool spec_ctrl_is_inconsistent(void);
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#endif
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diff --git a/migration/migration.c b/migration/migration.c
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index d780601f0c..d39c43c6b7 100644
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--- a/migration/migration.c
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+++ b/migration/migration.c
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@@ -2121,6 +2121,14 @@ static void migration_completion(MigrationState *s, int current_active_state,
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migrate_set_state(&s->state, current_active_state,
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MIGRATION_STATUS_COMPLETED);
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}
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+ if (spec_ctrl_is_inconsistent()) {
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+ fprintf(stderr, "WARNING! Migration from qemu with rudimentary "
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+ "Spectre v2 support to newer qemu\ndetected! To "
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+ "maintain proper protection, restart the guest as "
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+ "soon as possible\nusing the spec_ctrl cpu feature "
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+ "flag or a *-IBRS vcpu model specified\nas appropriate."
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+ "\n");
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+ }
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return;
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