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[PULL 079/153] i386/cpu: Reorganize dependency check for arch lbr state

Paolo Bonzini posted 153 patches 1 week, 4 days ago
Maintainers: "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Thomas Huth <thuth@redhat.com>, Yonggang Luo <luoyonggang@gmail.com>, Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Cameron Esfahani <dirty@apple.com>, Roman Bolshakov <rbolshakov@ddn.com>, Phil Dennis-Jordan <phil@philjordan.eu>, Mads Ynddal <mads@ynddal.dk>, Magnus Kulke <magnus.kulke@linux.microsoft.com>, Wei Liu <wei.liu@kernel.org>, Stefano Stabellini <sstabellini@kernel.org>, Anthony PERARD <anthony@xenproject.org>, Paul Durrant <paul@xen.org>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, David Hildenbrand <david@kernel.org>, Igor Mammedov <imammedo@redhat.com>, Alistair Francis <alistair.francis@wdc.com>, Stefan Berger <stefanb@linux.vnet.ibm.com>, John Snow <jsnow@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>, Aarushi Mehta <mehta.aaru20@gmail.com>, Julia Suvorova <jusual@redhat.com>, Stefano Garzarella <sgarzare@redhat.com>, Stefan Weil <sw@weilnetz.de>, Samuel Thibault <samuel.thibault@ens-lyon.org>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Zhao Liu <zhao1.liu@intel.com>, Peter Maydell <peter.maydell@linaro.org>, Mauro Carvalho Chehab <mchehab+huawei@kernel.org>, "Daniel P. Berrangé" <berrange@redhat.com>, Luc Michel <luc@lmichel.fr>, Damien Hedde <damien.hedde@dahe.fr>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Markus Armbruster <armbru@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Ani Sinha <anisinha@redhat.com>, Christian Schoenebeck <qemu_oss@crudebyte.com>, Greg Kurz <groug@kaod.org>, "Michael S. Tsirkin" <mst@redhat.com>, Dongjiu Geng <gengdongjiu1@gmail.com>, Aurelien Jarno <aurelien@aurel32.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Cédric Le Goater" <clg@kaod.org>, Steven Lee <steven_lee@aspeedtech.com>, Troy Lee <leetroy@gmail.com>, Jamin Lin <jamin_lin@aspeedtech.com>, Andrew Jeffery <andrew@codeconstruct.com.au>, Joel Stanley <joel@jms.id.au>, Tyrone Ting <kfting@nuvoton.com>, Hao Wu <wuhaotsh@google.com>, Beniamino Galvani <b.galvani@gmail.com>, Strahinja Jankovic <strahinja.p.jankovic@gmail.com>, Niek Linnenbank <nieklinnenbank@gmail.com>, Samuel Tardieu <sam@rfc1149.net>, Antony Pavlov <antonynpavlov@gmail.com>, Igor Mitsyanko <i.mitsyanko@gmail.com>, Jean-Christophe Dubois <jcd@tribudubois.net>, Andrey Smirnov <andrew.smirnov@gmail.com>, Bernhard Beschow <shentey@gmail.com>, Rob Herring <robh@kernel.org>, Subbaraya Sundeep <sundeep.lkml@gmail.com>, Jan Kiszka <jan.kiszka@web.de>, Felipe Balbi <balbi@kernel.org>, Radoslaw Biernacki <rad@semihalf.com>, Leif Lindholm <leif.lindholm@oss.qualcomm.com>, Eric Auger <eric.auger@redhat.com>, Alexandre Iooss <erdnaxe@crans.org>, Shannon Zhao <shannon.zhaosl@gmail.com>, Gerd Hoffmann <kraxel@redhat.com>, Laurent Vivier <laurent@vivier.eu>, Michael Rolnik <mrolnik@gmail.com>, Raphael Norwitz <raphael@enfabrica.net>, Helge Deller <deller@gmx.de>, "Clément Chigot" <chigot@adacore.com>, Frederic Konrad <konrad.frederic@yahoo.fr>, Alberto Garcia <berto@igalia.com>, Yoshinori Sato <yoshinori.sato@nifty.com>, Magnus Damm <magnus.damm@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Jason Herne <jjherne@linux.ibm.com>, Vijai Kumar K <vijai@behindbytes.com>, Nicholas Piggin <npiggin@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>, "Collin L. Walling" <walling@linux.ibm.com>, Amit Shah <amit@kernel.org>, Yanan Wang <wangyanan55@huawei.com>, Riku Voipio <riku.voipio@iki.fi>, Paul Burton <paulburton@kernel.org>, Aleksandar Rikalo <arikalo@gmail.com>, Jonathan Cameron <jonathan.cameron@huawei.com>, Fan Ni <fan.ni@samsung.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, "Hervé Poussineau" <hpoussin@reactos.org>, BALATON Zoltan <balaton@eik.bme.hu>, Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>, Dmitry Osipenko <dmitry.osipenko@collabora.com>, Dmitry Fleytman <dmitry.fleytman@gmail.com>, Ninad Palsule <ninad@linux.ibm.com>, Glenn Miles <milesg@linux.ibm.com>, "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>, Corey Minyard <cminyard@mvista.com>, Patrick Leis <venture@google.com>, Alejandro Jimenez <alejandro.j.jimenez@oracle.com>, Sairaj Kodilkar <sarunkod@amd.com>, Jason Wang <jasowang@redhat.com>, Yi Liu <yi.l.liu@intel.com>, "Clément Mathieu--Drif" <clement.mathieu--drif@eviden.com>, David Woodhouse <dwmw2@infradead.org>, Sergio Lopez <slp@redhat.com>, Alexander Graf <graf@amazon.com>, Dorjoy Chowdhury <dorjoychy111@gmail.com>, Song Gao <gaosong@loongson.cn>, Bibo Mao <maobibo@loongson.cn>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Huacai Chen <chenhuacai@kernel.org>, Jia Liu <proljc@gmail.com>, Gautam Menghani <gautam@linux.ibm.com>, Aditya Gupta <adityag@linux.ibm.com>, Xiao Guangrong <xiaoguangrong.eric@gmail.com>, Alexander Bulekov <alxndr@bu.edu>, Bandan Das <bsd@redhat.com>, Darren Kenny <darren.kenny@oracle.com>, Qiuhao Li <Qiuhao.Li@outlook.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Gustavo Romero <gustavo.romero@linaro.org>, Francisco Iglesias <francisco.iglesias@amd.com>, Pavel Pisa <pisa@cmp.felk.cvut.cz>, Vikram Garhwal <vikram.garhwal@bytedance.com>, Sriram Yagnaraman <sriram.yagnaraman@ericsson.com>, Max Filippov <jcmvbkbc@gmail.com>, Jiri Pirko <jiri@resnulli.us>, Sven Schnelle <svens@stackframe.org>, Stafford Horne <shorne@gmail.com>, Elena Ufimtseva <elena.ufimtseva@oracle.com>, Jagannathan Raman <jag.raman@oracle.com>, Chinmay Rath <rathc@linux.ibm.com>, Sai Pavan Boddu <sai.pavan.boddu@amd.com>, Ran Wang <wangran@bosc.ac.cn>, Anup Patel <anup.patel@wdc.com>, Eric Farman <farman@linux.ibm.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Tony Krowiak <akrowiak@linux.ibm.com>, Farhan Ali <alifm@linux.ibm.com>, Nina Schoetterl-Glausch <nsg@linux.ibm.com>, Jared Rossi <jrossi@linux.ibm.com>, Zhuoying Cai <zycai@linux.ibm.com>, Cornelia Huck <cohuck@redhat.com>, Hannes Reinecke <hare@suse.com>, Bin Meng <bmeng.cn@gmail.com>, Titus Rwantare <titusr@google.com>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Jeuk Kim <jeuk20.kim@samsung.com>, "Hongren (Zenithal) Zheng" <i@zenithal.me>, "Canokeys.org" <contact@canokeys.org>, John Levon <john.levon@nutanix.com>, Thanos Makatos <thanos.makatos@nutanix.com>, Alex Williamson <alex@shazbot.org>, Tomita Moeko <tomitamoeko@gmail.com>, Viresh Kumar <viresh.kumar@linaro.org>, Mathieu Poirier <mathieu.poirier@linaro.org>, Manos Pitsidianakis <manos.pitsidianakis@linaro.org>, "Gonglei (Arei)" <arei.gonglei@huawei.com>, Eric Blake <eblake@redhat.com>, Keith Busch <kbusch@kernel.org>, Klaus Jensen <its@irrelevant.dk>, Jesper Devantier <foss@defmacro.it>, Huai-Cheng Kuo <hchkuo@avery-design.com.tw>, Chris Browy <cbrowy@avery-design.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, "Dr. David Alan Gilbert" <dave@treblig.org>, Zhang Chen <zhangckid@gmail.com>, Li Zhijian <lizhijian@fujitsu.com>, Mahmoud Mandour <ma.mandourr@gmail.com>, Pierrick Bouvier <pierrick.bouvier@linaro.org>, Cleber Rosa <crosa@redhat.com>, Michael Roth <michael.roth@amd.com>, Maksim Davydov <davydov-max@yandex-team.ru>, David Gibson <david@gibson.dropbear.id.au>, Hyman Huang <yong.huang@smartx.com>, Brian Cain <brian.cain@oss.qualcomm.com>, Marcelo Tosatti <mtosatti@redhat.com>, Pedro Barbuda <pbarbuda@microsoft.com>, Mohamed Mediouni <mohamed@unpredictable.fr>, Coiby Xu <Coiby.Xu@gmail.com>
[PULL 079/153] i386/cpu: Reorganize dependency check for arch lbr state
Posted by Paolo Bonzini 1 week, 3 days ago 
From: Zhao Liu <zhao1.liu@intel.com>

The arch lbr state has 2 dependencies:
 * Arch lbr feature bit (CPUID 0x7.0x0:EDX[bit 19]):

   This bit also depends on pmu property. Mask it off if pmu is disabled
   in x86_cpu_expand_features(), so that it is not needed to repeatedly
   check whether this bit is set as well as pmu is enabled.

   Note this doesn't need compat option, since even KVM hasn't support
   arch lbr yet.

   The supported xstate is constructed based such dependency in
   cpuid_has_xsave_feature(), so if pmu is disabled and arch lbr bit is
   masked off, then arch lbr state won't be included in supported
   xstates.

   Thus it's safe to drop the check on arch lbr bit in CPUID 0xD
   encoding.

 * XSAVES feature bit (CPUID 0xD.0x1.EAX[bit 3]):

   Arch lbr state is a supervisor state, which requires the XSAVES
   feature support. Enumerate supported supervisor state based on XSAVES
   feature bit in x86_cpu_enable_xsave_components().

   Then it's safe to drop the check on XSAVES feature support during
   CPUID 0XD encoding.

Suggested-by: Zide Chen <zide.chen@intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251211060801.3600039-8-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index f4c0ae533d0..b53467eb997 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -8179,20 +8179,6 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             *ebx = xsave_area_size(xstate, true);
             *ecx = env->features[FEAT_XSAVE_XSS_LO];
             *edx = env->features[FEAT_XSAVE_XSS_HI];
-            if (kvm_enabled() && cpu->enable_pmu &&
-                (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_ARCH_LBR) &&
-                (*eax & CPUID_XSAVE_XSAVES)) {
-                *ecx |= XSTATE_ARCH_LBR_MASK;
-            } else {
-                *ecx &= ~XSTATE_ARCH_LBR_MASK;
-            }
-        } else if (count == 0xf && cpu->enable_pmu
-                   && (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_ARCH_LBR)) {
-            const ExtSaveArea *esa = &x86_ext_save_areas[count];
-
-            *eax = esa->size;
-            *ebx = esa->offset;
-            *ecx = esa->ecx;
         } else if (count < ARRAY_SIZE(x86_ext_save_areas)) {
             const ExtSaveArea *esa = &x86_ext_save_areas[count];
 
@@ -8910,6 +8896,12 @@ static void x86_cpu_enable_xsave_components(X86CPU *cpu)
 
     mask = 0;
     for (i = 0; i < ARRAY_SIZE(x86_ext_save_areas); i++) {
+        /* Skip supervisor states if XSAVES is not supported. */
+        if (CPUID_XSTATE_XSS_MASK & (1 << i) &&
+            !(env->features[FEAT_XSAVE] & CPUID_XSAVE_XSAVES)) {
+            continue;
+        }
+
         const ExtSaveArea *esa = &x86_ext_save_areas[i];
         if (cpuid_has_xsave_feature(env, esa)) {
             mask |= (1ULL << i);
@@ -9027,11 +9019,13 @@ void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
         }
     }
 
-    if (!cpu->pdcm_on_even_without_pmu) {
+    if (!cpu->enable_pmu) {
         /* PDCM is fixed1 bit for TDX */
-        if (!cpu->enable_pmu && !is_tdx_vm()) {
+        if (!cpu->pdcm_on_even_without_pmu && !is_tdx_vm()) {
             env->features[FEAT_1_ECX] &= ~CPUID_EXT_PDCM;
         }
+
+        env->features[FEAT_7_0_EDX] &= ~CPUID_7_0_EDX_ARCH_LBR;
     }
 
     for (i = 0; i < ARRAY_SIZE(feature_dependencies); i++) {
-- 
2.52.0

Patchew 2.1-devel-b67e4c2

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