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From e6f541bd5eea74185e34e41e628d52cfc5ab7b6a Mon Sep 17 00:00:00 2001
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From: Eduardo Habkost <ehabkost@redhat.com>
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Date: Thu, 26 Jul 2018 17:19:03 +0100
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Subject: [PATCH 13/14] i386: Remove generic SMT thread check
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RH-Author: Eduardo Habkost <ehabkost@redhat.com>
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Message-id: <20180726171904.27418-11-ehabkost@redhat.com>
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Patchwork-id: 81532
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O-Subject: [qemu-kvm RHEL8/virt212 PATCH v2 10/11] i386: Remove generic SMT thread check
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Bugzilla: 1597739
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
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RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
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From: Babu Moger <babu.moger@amd.com>
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Remove generic non-intel check while validating hyperthreading support.
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Certain AMD CPUs can support hyperthreading now.
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CPU family with TOPOEXT feature can support hyperthreading now.
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Signed-off-by: Babu Moger <babu.moger@amd.com>
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Tested-by: Geoffrey McRae <geoff@hostfission.com>
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Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
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Message-Id: <1529443919-67509-4-git-send-email-babu.moger@amd.com>
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Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
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(cherry picked from commit 6b2942f966d5e54c37d305c80f5f98d504c2bc55)
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Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 target/i386/cpu.c | 17 +++++++++++------
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 1 file changed, 11 insertions(+), 6 deletions(-)
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diff --git a/target/i386/cpu.c b/target/i386/cpu.c
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index fe2b2e8..8647109 100644
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--- a/target/i386/cpu.c
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+++ b/target/i386/cpu.c
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@@ -4952,17 +4952,22 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
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     qemu_init_vcpu(cs);
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-    /* Only Intel CPUs support hyperthreading. Even though QEMU fixes this
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-     * issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
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-     * based on inputs (sockets,cores,threads), it is still better to gives
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+    /*
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+     * Most Intel and certain AMD CPUs support hyperthreading. Even though QEMU
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+     * fixes this issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
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+     * based on inputs (sockets,cores,threads), it is still better to give
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      * users a warning.
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      *
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      * NOTE: the following code has to follow qemu_init_vcpu(). Otherwise
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      * cs->nr_threads hasn't be populated yet and the checking is incorrect.
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      */
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-    if (!IS_INTEL_CPU(env) && cs->nr_threads > 1 && !ht_warned) {
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-        error_report("AMD CPU doesn't support hyperthreading. Please configure"
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-                     " -smp options properly.");
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+     if (IS_AMD_CPU(env) &&
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+         !(env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) &&
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+         cs->nr_threads > 1 && !ht_warned) {
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+            error_report("This family of AMD CPU doesn't support "
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+                         "hyperthreading(%d). Please configure -smp "
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+                         "options properly or try enabling topoext feature.",
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+                         cs->nr_threads);
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         ht_warned = true;
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     }
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-- 
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1.8.3.1
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