From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (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 C4BDE32ABFD; Mon, 8 Dec 2025 09:34:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765186479; cv=none; b=N1iRIjKkzslFKxLxjKfG1XNUui16G9ucLg49f9hhZAmobmhQDWX48AaYuZzFcUmttpIkpztgf0OIkAit5BwcWedt4Uro7B73bJjQ8SM+wjWSELXk1mSs8AfvgTlLD2lQE0Su7nRX8Po6875WL7FxSHSK9Y6Uf0lrzZLtBQ7pP+I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765186479; c=relaxed/simple; bh=nSxjb3iSvlhZrRlAmKEmJNxO+kFHROtO7j/bMcBHd/4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tfVzW4bgCkVwVDQGwL9vceJj1/8C0jbzqrktpKKdZ97UCNoGA3/franYO823ruuZz8/sQpAAxF2qHPHsRUQkzDfDPhGfhpUn3/EXC3NFKQu2eVUb2JZe0QHDyAeI466OHYLyPxByjF5Hx5NTW2zLHdrr2dx7pH+LGDKUr+Dgt44= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=R7lz10Q+; arc=none smtp.client-ip=198.175.65.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="R7lz10Q+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1765186478; x=1796722478; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=nSxjb3iSvlhZrRlAmKEmJNxO+kFHROtO7j/bMcBHd/4=; b=R7lz10Q++QcRVjVH87R4YTbCHfkZB7IwmHerzxrLLhmN9rgtC2K7oXkI LubgVKvoFigNJv1qXvFFaFecYY7KfCytMLdYcgUlIHgIaaQpGTlZlTYmO 4bZZU9cOJyDuBnE2crCW6uOuy5AJ8NrxdT+E2udv6RrNzgWUBcOXDfCn9 ug8Jf0T3fZqkaUybgOsyL2oXwBP3CwY6DnJZQujrR930S5c87C5d2nveH p0k02dc6anqKZ1LGT43NeKiWrhEqvGqNDvghqQgOsrys56iXCJ2c0EuNq 73DYD8A/4SlCWBSkvtqWJujsUnj/zwrrKuegSvJPuHlAP6U2AyJpBLunS Q==; X-CSE-ConnectionGUID: ivHioeq3S2S642p7NS0K0g== X-CSE-MsgGUID: W/0Bz5joT969CG0McuNgjA== X-IronPort-AV: E=McAfee;i="6800,10657,11635"; a="67288121" X-IronPort-AV: E=Sophos;i="6.20,258,1758610800"; d="scan'208";a="67288121" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Dec 2025 01:34:38 -0800 X-CSE-ConnectionGUID: jJDDhXNuTkyNrjKmaswHjw== X-CSE-MsgGUID: 4F6FhXpxRu6nERmNjwerUg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.20,258,1758610800"; d="scan'208";a="196157352" Received: from dapengmi-mobl1.ccr.corp.intel.com (HELO [10.124.240.12]) ([10.124.240.12]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Dec 2025 01:34:30 -0800 Message-ID: <04c70698-e523-43ae-9092-f360c848d797@linux.intel.com> Date: Mon, 8 Dec 2025 17:34:27 +0800 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 39/44] KVM: VMX: Bug the VM if either MSR auto-load list is full To: Sean Christopherson , Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Xin Li , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Paolo Bonzini Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Mingwei Zhang , Xudong Hao , Sandipan Das , Xiong Zhang , Manali Shukla , Jim Mattson References: <20251206001720.468579-1-seanjc@google.com> <20251206001720.468579-40-seanjc@google.com> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: <20251206001720.468579-40-seanjc@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/6/2025 8:17 AM, Sean Christopherson wrote: > WARN and bug the VM if either MSR auto-load list is full when adding an > MSR to the lists, as the set of MSRs that KVM loads via the lists is > finite and entirely KVM controlled, i.e. overflowing the lists shouldn't > be possible in a fully released version of KVM. Terminate the VM as the > core KVM infrastructure has no insight as to _why_ an MSR is being added > to the list, and failure to load an MSR on VM-Enter and/or VM-Exit could > be fatal to the host. E.g. running the host with a guest-controlled PEBS > MSR could generate unexpected writes to the DS buffer and crash the host. > > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/vmx/vmx.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 38491962b2c1..2c50ebf4ff1b 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -1098,6 +1098,7 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr, > { > int i, j = 0; > struct msr_autoload *m = &vmx->msr_autoload; > + struct kvm *kvm = vmx->vcpu.kvm; > > switch (msr) { > case MSR_EFER: > @@ -1134,12 +1135,10 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr, > i = vmx_find_loadstore_msr_slot(&m->guest, msr); > j = vmx_find_loadstore_msr_slot(&m->host, msr); > > - if ((i < 0 && m->guest.nr == MAX_NR_LOADSTORE_MSRS) || > - (j < 0 && m->host.nr == MAX_NR_LOADSTORE_MSRS)) { > - printk_once(KERN_WARNING "Not enough msr switch entries. " > - "Can't add msr %x\n", msr); > + if (KVM_BUG_ON(i < 0 && m->guest.nr == MAX_NR_LOADSTORE_MSRS, kvm) || > + KVM_BUG_ON(j < 0 && m->host.nr == MAX_NR_LOADSTORE_MSRS, kvm)) nit: Remove one extra space before "m->host.nr". > return; > - } > + > if (i < 0) { > i = m->guest.nr++; > vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);