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Peter Anvin" References: <20260806015233.202486-1-jason.andryuk@amd.com> <083db883-558a-4000-b404-bf170c8309ee@suse.com> <62b5117f-928d-4908-9217-cc16d9cf15f9@suse.com> <967208c9-8d51-4380-8cb4-298f5c313d35@suse.com> <3206813c-33fc-476f-a553-4d3f319459aa@suse.com> Content-Language: en-US From: Jason Andryuk In-Reply-To: <3206813c-33fc-476f-a553-4d3f319459aa@suse.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN3PEPF0000B076:EE_|SJ2PR12MB8881:EE_ X-MS-Office365-Filtering-Correlation-Id: f3c6461b-1d28-43cc-22d0-08def3c2cebb X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|36860700016|82310400026|376014|23010399003|1800799024|10067099003|56012099006|11063799006|4143699003|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 1CP4srme/UHBIZGwwigWh27iMkxSgnH8KnZR+Z6lRwdzyEmO3jDsL7g11H20DH0zJsmSrYWXu87oRXUtKsqf0dLK2KR4gMaxOCUyR59I6RiZKVfIcnaPouPCIfx+dVY5w+qyO2mNmpXKQ2UVJys+szvD82NptQxc05IhBzjErmRQqCUsU2zDe5yekVHNIu0S/QWpiPV/eOA0sZwC16Jb3RZ60EShNLZLsqCWcV+i3mhw5NBYkU/c9lKl5Xf6yAcovk4kughjseetQK7qNZC42xNLWr5rf1iPsmKYrMC2qGrpKEOZ9iOV7JzLJm7+/+OFlyDTa8+OeJfljZMdUzyhxVqo1is2D/sZC108QL1/zqqn/3b/zLPpf0nMXAsTB4khuGGh8TaE2zTdXlUO9hdrONtg+789oTPnXO67opkquXHqcI/HmUZ18Z94p4Ukmh1ivtGHope3p4qD8+8C/XxCHx4KkrPIuxDxumNpr/5IqWZ8afzjjuL0jm+BkF+nfVuhQXfOHA7HF99hHTkh6X9QqnPFmiTdhx4GkITiUTG6hIfkEJKr4BsNsI3RJNZ9rDB/JM7dicyuuEO6UGdPCGJFKrhFH92AiTKbbrFp3vH0SxsgnLbe2A6xmxxyC6vINFIftzGRFC0cIlXOaE7L59YoU5/94uRAb/xYi4AY5UHLp9Od+JMYTUK7JHasP+9AO3AQ X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(7416014)(36860700016)(82310400026)(376014)(23010399003)(1800799024)(10067099003)(56012099006)(11063799006)(4143699003)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: k1G1CMbkAWeDRKUcpL9U6a5ZkMlBqQ0lfIdWEzQs9SEm4hCMYmfZRAbhdBN5Pl8WilMkQ6vJKypVT69PSFkwm4Deex68hAFC2yALUMJ5HAZQdKZd5WrbSSUb1QsIrFeOMHcHbOKoGJoHAaRZ2oFdHf+8B20MzpP1Tl7EEP5VCxm5u1eNSQ62JfIQeSQaiRYIW5NAKAYZJ1rHFdgprnkNvVmoLI3g9QlKVtIRsjV2wfNKIeQB/+nevp+IuP51sIeJMA+UplboLDt4dytCv0vPoVLKhRraMEUXFegGXKT5yhs6KkqH6guTrjP99MdQUIfm7isrpITGGdolc+jdKHHMbrVB/lMkNUwUcuhjOcpOD8IgLHdZZs6ZZkF9hsT22EOvswAFal71mTlsZitArm6k7VfKBZsBkbGU46pvPVqUHG0KowWrKJJuH0+29JKLEuQS X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Aug 2026 13:58:35.0349 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f3c6461b-1d28-43cc-22d0-08def3c2cebb X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN3PEPF0000B076.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB8881 On 2026-08-06 09:31, Juergen Gross wrote: > On 06.08.26 15:24, Jason Andryuk wrote: >> On 2026-08-06 08:00, Jürgen Groß wrote: >>> On 06.08.26 13:31, Jan Beulich wrote: >>>> On 06.08.2026 12:55, Juergen Gross wrote: >>>>> On 06.08.26 03:52, Jason Andryuk wrote: >>>>>> Allow disabling XEN_PVHVM for a PV-only.  A stub in the event channel >>>>>> code needs to be fixed first. >>>>>> >>>>>> Jason Andryuk (2): >>>>>>     xen/events: Fix xen_set_upcall_vector stub >>>>>>     xen/Kconfig: select XEN_PVHVM >>>>>> >>>>>>    arch/x86/xen/Kconfig             | 8 +++++--- >>>>>>    drivers/xen/events/events_base.c | 2 +- >>>>>>    2 files changed, 6 insertions(+), 4 deletions(-) >>>>>> >>>>> >>>>> I did a comparison of a kernel built with your patches disabling >>>>> XEN_PVHVM >>>>> and my patches with XEN_PVHVM_GUEST disabled. >>>>> >>>>> The kernel built with my patches is 6 bytes smaller than the one >>>>> with your >>>>> patches. >>>> >>>> Isn't this a sign of something else needing tweaking, somewhere? >>> >>> This is a sign that there are probably only very few really HVM >>> specific paths >>> (in the sense of: explicitly not marked as irrelevant for PV) in the >>> kernel. >>> Yes, I'm sure you can find some more, but I'm really not sure this is >>> relevant >>> for more than a handful of users. >> >> I see more reduction: >> 15029248 - arch/x86/boot/bzImage >> 15021056 - arch/x86/boot/bzImage.after >> >> ~8k >> >> 52542480 - vmlinux >> 52523184 - vmlinux.after >> >> ~18k >> >> $ ../linux/scripts/bloat-o-meter vmlinux vmlinux.after >> add/remove: 1/136 grow/shrink: 14/48 up/down: 15902/-22430 (-6528) > > Did you disable CONFIG_XEN_PVHVM_GUEST in the before kernel, too? Yes $ grep PVHVM config-before config-after config-pvh-before:CONFIG_XEN_PVHVM=y config-pvh-before:CONFIG_XEN_PVHVM_SMP=y config-pvh-before:# CONFIG_XEN_PVHVM_GUEST is not set config-pvh-after:# CONFIG_XEN_PVHVM_GUEST is not set These three options change: $ diff -u config-before config-after -CONFIG_XEN_PVHVM=y -CONFIG_XEN_PVHVM_SMP=y -CONFIG_XEN_AUTO_XLATE=y Regards, Jason