From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f173.google.com (mail-lj1-f173.google.com [209.85.208.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51A677C for ; Fri, 24 Jun 2022 16:36:13 +0000 (UTC) Received: by mail-lj1-f173.google.com with SMTP id by38so3349116ljb.10 for ; Fri, 24 Jun 2022 09:36:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=v0kR56a3js8tVSJ/80FTzZmMgZbMcBIHC4Horg01B0c=; b=VHI4cibUu1nlWHaj0e1TN23hEBzchsJwNJ7pRPD9JLXj/JbuL64WYgN1Dd1IRkvPac ygipsK+DMHwpIQRsRsbkPu/+djsjTlnueymy5PTClA6o5M5jXIqwHrOIrFtmNyXbhiAY kCHtINfa6mI7k46ERe3C4mRVz9huLOLE/9ERK2CbRPYKdq9/dVDOC7BDdmQJZOQ9L3rh kHTOpCht0iCElT4L53YjSkh8ELGmiV/61uC9oA5sOwy8KOLsBFEPRq1xqbTaVTAqzzHA rrsXjD2OIPdEy28yftHFvR5TnUVUVvdaKNm4ZmDwswT0iDB3YQ+h16vkjyIlglLcnDlR Wp6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=v0kR56a3js8tVSJ/80FTzZmMgZbMcBIHC4Horg01B0c=; b=Z/412LJGNJnAC/O5hxh4gdu72Hkt/gckPzSjpIZtXj+97q2kw2D99CqONDTSsZpG9/ oys3z7yadbERzNU1eCJ5asRZfH2fAQBk0cQnQAXXZd2/T0xOpjHDpJ28srZmByey0Odk RQnJNZSdyP9uok9LB5UZaw8EU5H6svpTg/CVlIR9N7xBvAAxMYX3m6etgnD3SWsycCCk DOSnVanAM0vjyaBpCaUmNgfktX3NjkZpWEWgj2RKLIfs083D0YiyjbfvWxFQf9ACpjXP ooEVeXGaHvf8A94u7dk8HECpYKKG5S3RboE/MFt+gCxusEHozj7jCvuoTXdOVPE2f2SF eZcQ== X-Gm-Message-State: AJIora9skjBgM8CCa/43OXGuZyGYCFdx4MCNBjCJ7ugZSfeYTt0uduKK 3Wi4w7tYWIkpQP/MGGEtcJjBNNU9PmVFGAeNe6oN/KW1Gm83AQ== X-Google-Smtp-Source: AGRyM1vL+EaPdx915agnP8RGtkdwEKmVIyCaqnwD+c2dfRqzuQVoNAkH4rIjSHdD14nbycbqpt00uWwh6peuqigJjOg= X-Received: by 2002:a2e:22c6:0:b0:25a:8c16:baf with SMTP id i189-20020a2e22c6000000b0025a8c160bafmr6868072lji.132.1656088571108; Fri, 24 Jun 2022 09:36:11 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <1dbc14735bbc336c171ef8fefd4aef39ddf95816.1655761627.git.ashish.kalra@amd.com> In-Reply-To: <1dbc14735bbc336c171ef8fefd4aef39ddf95816.1655761627.git.ashish.kalra@amd.com> From: Peter Gonda Date: Fri, 24 Jun 2022 10:35:59 -0600 Message-ID: Subject: Re: [PATCH Part2 v6 47/49] *fix for stale per-cpu pointer due to cond_resched during ghcb mapping To: Ashish Kalra Cc: "the arch/x86 maintainers" , LKML , kvm list , linux-coco@lists.linux.dev, linux-mm@kvack.org, Linux Crypto Mailing List , Thomas Gleixner , Ingo Molnar , Joerg Roedel , "Lendacky, Thomas" , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Borislav Petkov , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , Tony Luck , Marc Orr , Sathyanarayanan Kuppuswamy , Alper Gun , "Dr. David Alan Gilbert" , jarkko@kernel.org Content-Type: text/plain; charset="UTF-8" On Mon, Jun 20, 2022 at 5:15 PM Ashish Kalra wrote: > > From: Michael Roth > > Signed-off-by: Michael Roth Can you add a commit description here? Is this a fix for existing SEV-ES support or should this be incorporated into a patch in this series which adds this issue? > --- > arch/x86/kvm/svm/svm.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index fced6ea423ad..f78e3b1bde0e 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -1352,7 +1352,7 @@ static void svm_vcpu_free(struct kvm_vcpu *vcpu) > static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu) > { > struct vcpu_svm *svm = to_svm(vcpu); > - struct svm_cpu_data *sd = per_cpu(svm_data, vcpu->cpu); > + struct svm_cpu_data *sd; > > if (sev_es_guest(vcpu->kvm)) > sev_es_unmap_ghcb(svm); > @@ -1360,6 +1360,10 @@ static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu) > if (svm->guest_state_loaded) > return; > > + /* sev_es_unmap_ghcb() can resched, so grab per-cpu pointer afterward. */ > + barrier(); > + sd = per_cpu(svm_data, vcpu->cpu); > + > /* > * Save additional host state that will be restored on VMEXIT (sev-es) > * or subsequent vmload of host save area. > -- > 2.25.1 >