From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE7A32DFF04; Wed, 8 Jul 2026 15:42:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783525326; cv=none; b=InhMx2p4YzLRv1NK74/3ARQQx+RogxH9FePQjMKAem3jujGKuCkqnKNNGJpdUb2NUftLB8KAamfnSCPYeiz2tZn5okGmb5Crerx1bMIoWND4g2MGrA/+/aO+V708WTNRsFYWPSyaLoo0ud9Rt64yvB9G1Azwg5MYpr+YYYWLteA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783525326; c=relaxed/simple; bh=h9IbvOGqce5jMK4IWXHEhleScCe4RkKQUnlmN1EOwrc=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=RnM+zI8Eut451+iFfU2GZcl0uW8R+U4hfK30TvB07XSV13g6ERr9nKx8wB0JsYG1OCJBMCdHNtgE6JuDmKmh5OxSYl5Q7mWcZYd1n7DlZFRJyS/lnmoYFnGUK/UF0rtjmTZcprdzvwuW9B4A0GgmElGtMXUnmJlGjBmUmXaPhFs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=d59hYOZ5; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="d59hYOZ5" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=h9IbvOGqce5jMK4IWXHEhleScCe4RkKQUnlmN1EOwrc=; b=d59hYOZ5emvwyIode+FO8PQHCW hOfcYL6Tvi5ZuY2q/7JB/LUzfXfFOnQJTiggW8iRjAYpkyxfODGNquMZusuhotjndqqN4FjlintH/ ARSPdUY2mn/Wq9kfQMy3491lUymKy5UzXk4i+6aDJ86YM1Kml6S6iEibGwY3FJ7agzJvZ+bCd0b8w k0C7Kfjd0wscB4a0XG1AlT/iVM8nMt6YhVqO51D1G+xelZ6NiaKZ/TX271LHE3lh/Zq4arF2kJzZu mTCzrA8Ip9M4JTT5etBUkeqQlOcm8QuydSwfGBaEmAZPMtdSYLk7DkU0b61sPSUGdrOngMOYranLX dGhvnaEg==; Received: from [2001:8b0:10b:5:bad8:d14c:3672:7028] (helo=u09cd745991455d.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1whUPH-00000002y0P-2zeq; Wed, 08 Jul 2026 15:41:51 +0000 Message-ID: Subject: Re: [PATCH 8/8] KVM: x86/xen: Use 32-bit locked ops in kvm_xen_inject_pending_events() From: David Woodhouse To: Sean Christopherson Cc: Paul Durrant , Hyunwoo Kim , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 08 Jul 2026 16:41:50 +0100 In-Reply-To: References: <20260605143034.3603-1-dwmw2@infradead.org> <20260605143034.3603-9-dwmw2@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-E5A0bx0TSsENhkszGEZT" User-Agent: Evolution 3.60.3-0ubuntu1~ppa9~24.04 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html --=-E5A0bx0TSsENhkszGEZT Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2026-07-08 at 08:23 -0700, Sean Christopherson wrote: > This is... impressive?=C2=A0 Related to the above comment about there bei= ng two separate > atomic operation, only the access to vi->evtchn_pending_sel needs to deal= with > potential split-lock issues.=C2=A0 And there's zero to handle the NOT in = the asm blob. >=20 > Rather than munge the 32-bit and 64-bit cases together, just manually han= dle the > case where the bitwise-OR needs to be chunked in two. Yeah... that seems a whole lot more sensible than the ... "impressive" version. I think I got a bit lost there... :) Thanks. --=-E5A0bx0TSsENhkszGEZT Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCD9Aw ggSOMIIDdqADAgECAhAOmiw0ECVD4cWj5DqVrT9PMA0GCSqGSIb3DQEBCwUAMGUxCzAJBgNVBAYT AlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xJDAi BgNVBAMTG0RpZ2lDZXJ0IEFzc3VyZWQgSUQgUm9vdCBDQTAeFw0yNDAxMzAwMDAwMDBaFw0zMTEx MDkyMzU5NTlaMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYDVQQDExdWZXJv a2V5IFNlY3VyZSBFbWFpbCBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMjvgLKj jfhCFqxYyRiW8g3cNFAvltDbK5AzcOaR7yVzVGadr4YcCVxjKrEJOgi7WEOH8rUgCNB5cTD8N/Et GfZI+LGqSv0YtNa54T9D1AWJy08ZKkWvfGGIXN9UFAPMJ6OLLH/UUEgFa+7KlrEvMUupDFGnnR06 aDJAwtycb8yXtILj+TvfhLFhafxroXrflspavejQkEiHjNjtHnwbZ+o43g0/yxjwnarGI3kgcak7 nnI9/8Lqpq79tLHYwLajotwLiGTB71AGN5xK+tzB+D4eN9lXayrjcszgbOv2ZCgzExQUAIt98mre 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