[{"id":3668525,"web_url":"http://patchwork.ozlabs.org/comment/3668525/","msgid":"<777690A0-00B9-4594-BEC1-01F0C85BD438@unpredictable.fr>","list_archive_url":null,"date":"2026-03-24T15:20:09","subject":"Re: [PATCH v3 00/12] whpx: i386: Windows 10 and performance fixes","submitter":{"id":91318,"url":"http://patchwork.ozlabs.org/api/people/91318/","name":"Mohamed Mediouni","email":"mohamed@unpredictable.fr"},"content":"> On 24. Mar 2026, at 16:13, Mohamed Mediouni wrote:\n> \n> On Windows 10, the paravirtualisation enlightenments aren't available.\n> And neither is performance monitoring. Using the former as a gate to\n> operate in a reduced-functionality mode on Windows 10.\n> \n> And on the performance side, some state is really expensive to fetch\n> or write with Hyper-V so switch some less-essential state to on demand.\n> \n> The effect of this is magnified on Windows 10 because Hyper-V enlightenments\n> are not available there.\n> \n\nSome performance numbers from https://gitlab.com/qemu-project/qemu/-/work_items/3349\non Windows 10:\n\nQEMU 10.2: 2 minutes\nQEMU 11.0rc0: 8 minutes\nThis series: back to 2 minutes\n\nThis brings us to performance parity with older QEMU using winhvemulation \non Windows 10.\n\n> Side note: On Windows 11, use WHP with kernel-irqchip=on. On Windows 10, looks\n> like issues there are still lingering, with issues #289 and #346 still problematic.\n> \n> v1 -> v2:\n> - fix x86 HVF compatibility\n> - small nits\n> - added workaround for an issue that showed up during 32-bit Linux boot\n> on AMD\n> \n> v2 -> v3:\n> - Remove ad-hoc workaround in segment fetching and replace it by something\n> more proper.\n> The affected commits are \"whpx: i386: fetch segments on-demand\". The old\n> workaround separate commit is no longer present (or needed)\n> \n> Issue number: https://gitlab.com/qemu-project/qemu/-/work_items/3349\n> \n> Mohamed Mediouni (12):\n> whpx: i386: workaround for Windows 10 support\n> whpx: i386: enable exceptions VM exit only when needed\n> whpx: i386: skip TSC read for MMIO exits\n> whpx: i386: skip XCRs read for MMIO exits\n> whpx: i386: don't restore segment registers after MMIO handling\n> target/i386: emulate: add new callbacks\n> whpx: i386: add implementation of new x86_emul_ops\n> target/i386: emulate: indirect access to CRs\n> whpx: i386: indirect access to CRs\n> target/i386: emulate: segmentation rework\n> whpx: i386: fetch segments on-demand\n> whpx: i386: fast runtime state reads\n> \n> target/i386/emulate/x86_emu.h | 6 +\n> target/i386/emulate/x86_helpers.c | 83 +++++----\n> target/i386/emulate/x86_mmu.c | 11 +-\n> target/i386/hvf/x86.c | 11 ++\n> target/i386/whpx/whpx-all.c | 280 +++++++++++++++++++++++++-----\n> 5 files changed, 302 insertions(+), 89 deletions(-)\n> \n> -- \n> 2.50.1 (Apple Git-155)\n>","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=unpredictable.fr header.i=@unpredictable.fr\n header.a=rsa-sha256 header.s=sig1 header.b=QKoAWovF;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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helo=outbound.ms.icloud.com","X-Spam_score_int":"-27","X-Spam_score":"-2.8","X-Spam_bar":"--","X-Spam_report":"(-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}},{"id":3668597,"web_url":"http://patchwork.ozlabs.org/comment/3668597/","msgid":"<20260324171900.794207-2-pbonzini@redhat.com>","list_archive_url":null,"date":"2026-03-24T17:19:01","subject":"Re: [PATCH v3 00/12] whpx: i386: Windows 10 and performance fixes","submitter":{"id":2701,"url":"http://patchwork.ozlabs.org/api/people/2701/","name":"Paolo Bonzini","email":"pbonzini@redhat.com"},"content":"Queued, thanks. Perhaps you can make target/i386/emulate remember\nthe registers it has already queried, and cache them in to env?\n\nPaolo","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=hwgTJajh;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=google header.b=quUeXBLs;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fgGxq4yR4z1xy1\n\tfor ; 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