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 7FAD43A3E68; Mon, 11 May 2026 12:59:55 +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=1778504399; cv=none; b=oPOBoGgICp0AovOKemINAGQu9hixbd8c7X0KKy8AMB+sL41Rmd8+JcM8cKqt/3cQ9E2uVMrGJo+6QkHMve1wK+nqbM3yR9NUcPMYAjE+HJ0cXUjd66fSiIk9eIN2S1Yxt1mRcS14ZMzJVYKL2+uSfsJSusWdPNtsqgYwrGIFs+M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778504399; c=relaxed/simple; bh=hPGhLXAH1iqfwlfrAgc4KhXKM/sxhzMPQqglokN1wFg=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=fCoTX2B1SsK1pCHt/41KDsMji82m9PCj/GPkyiNZZ002jcpa+aAFvK+KegUJDD8voFPLgQeLRGGkCbPpvmNzb2Uit47qXyJxBktcBKGrbI8g8W/nFSalRP8IgopQiOgnPnUqiLRkRunTxt1cARvgwcs/lnpMeY7zm8VlzJ1B0FM= 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=H/o4ryWH; 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="H/o4ryWH" 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=hPGhLXAH1iqfwlfrAgc4KhXKM/sxhzMPQqglokN1wFg=; b=H/o4ryWHICVNvvZLnSv4JaaK6s aOCSBIn9hpfY9GzhTosfaLcswJVJ0Xovo7j3/0mK07x7PnQBziVZ5jFBefXp0zsAd5JiMuEnlYnhK YFa8Qnbhus60MPqIpX2ZvdDGBG27SJBpBDljOVZot7Zipv+rzadAoiZTX/ZJEMAe6JngV65l7N++d skabxPWMw68vG/ysQdCxVqNV4bNCJ0n+/syITQJ7y4yR0ggYUDN70tz0WOmkX8xAw4iUC8HrMtyu2 yuo3dBP28xl7sSz88QE+MF8v5qJhUwz+d22QBmXpTIQGFBzA0AewToIg3kWok3wxe9oCJ9KD3NMLv 9cUIILRA==; Received: from 54-240-197-234.amazon.com ([54.240.197.234] helo=u09cd745991455d.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wMQEj-00000008CYg-0YmJ; Mon, 11 May 2026 12:59:53 +0000 Message-ID: <24df4dabec1328591f9996f00a298660bc0860e3.camel@infradead.org> Subject: Re: [PATCH 2/2] x86/kvm/vmx: Fix VMX vs hrtimer_rearm_deferred() From: David Woodhouse To: Peter Zijlstra , tglx@kernel.org Cc: linux-kernel@vger.kernel.org, Sean Christopherson , Jim Mattson , Binbin Wu , Vishal L Verma , "kvm@vger.kernel.org" , Rick P Edgecombe , Binbin Wu , "x86@kernel.org" , Paolo Bonzini Date: Mon, 11 May 2026 13:59:52 +0100 In-Reply-To: <20260423155936.957351833@infradead.org> References: <20260423155611.216805954@infradead.org> <20260423155936.957351833@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-4BUM8y+361YeLRHQRpK6" User-Agent: Evolution 3.52.3-0ubuntu1.1 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 --=-4BUM8y+361YeLRHQRpK6 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2026-04-23 at 17:56 +0200, Peter Zijlstra wrote: > Vishal reported that KVM unit test 'x2apic' started failing after commit > 0e98eb14814e ("entry: Prepare for deferred hrtimer rearming"). >=20 > The reason is that KVM/VMX is injecting interrupts while it has IRQs disa= bled, > for a context that will enable IRQs, this means that regs->flags.X86_EFLA= GS_IF > =3D=3D 0 and the irqentry_exit() will not DTRT. >=20 > Notably, irqentry_exit() must not call hrtimer_rearm_deferred() when the = return > context does not have IF set, because this will cause problems vs NMIs. >=20 > Therefore, fix up the state after the injection. >=20 > Fixes: 0e98eb14814e ("entry: Prepare for deferred hrtimer rearming") > Reported-by: "Verma, Vishal L" > Closes: https://lore.kernel.org/r/70cd3e97fbb796e2eb2ff8cd4b7614ada05a5f2= 4.camel%40intel.com > Suggested-by: Thomas Gleixner > Signed-off-by: Peter Zijlstra (Intel) > Tested-by: "Verma, Vishal L" Tested-by: David Woodhouse I don't see this being merged yet? Without this, Xen timer delivery (tested by the xen_shinfo_test KVM selftest) is failing. I think the Fixes: tag is wrong though; it actually broke with commit 15dd3a948855 ("hrtimer: Push reprogramming timers into the interrupt return path"), didn't it? --=-4BUM8y+361YeLRHQRpK6 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 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