From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (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 DAB9D3C16 for ; Thu, 2 Nov 2023 15:44:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Xpyoj7E7" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-5b064442464so15880807b3.3 for ; Thu, 02 Nov 2023 08:44:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698939894; x=1699544694; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=MWop9ChiDn+5U1d7ZFSKgT7XQaKJkOCdphsca+5hdRc=; b=Xpyoj7E79s5/x5vpanG63dDabLQxCxZ1xI6+3j0BPp0GvTwoIUZfAxMxqEk6as25S+ soyhtb18GLfH5PM39hkY8Rfk7ivfyj3zeBjRmfx842d8TelPuz86YPw/LeiDKjYc303V U5vnOcIXPJP3UaZsa/MEYBvrNcYxp71cnOX4ttvReNdWXhBGo85a5w2QSI16wCb5TD6f Fofed+bsalEieLvFsuvLypRUe76MlchsWePSwftpBmVfOO0+OGBHaGiybSmd+k58LhIK zb187RToc4MZ9XsA+sqrPRa9wPUAECeBrEdIZKW1osVnnfzcsLgSzFcCzu/eX6CB+Ic8 q86A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698939894; x=1699544694; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=MWop9ChiDn+5U1d7ZFSKgT7XQaKJkOCdphsca+5hdRc=; b=BLRFN+VZ27K4bBHub44fP9WCShewBLNmr7uxyjh0aSX+C6KwJOa8CHbMP95tPBlZKv ykGioydwYsVt7UTkq6+fzt/TQab61RrYJMwcnGMdaHgT9i5/Gnn1i7t3p7kovJu/xw0x SVGinBMySVbeQUNqvWrYc2ewmpSLcfUbwOHgdIrSe/Cj2Vxraq1nEvQ3+OjQm2zoWcs7 o2HlJP44QWiAUwjEAE8K93UFR5/h4nFf+IwB8Zx3gRvNpfVEuvPyjqwxSa7iVkBGKV5k UO50ub8WEXqQUZcA5wd2vKf34eG+Vufgrz2U+3Wc426Bdkwu8DrcUy4Yb2sSXqSyf2pc Ii0Q== X-Gm-Message-State: AOJu0Yx2d0wmnmCo7Q+TMtk+WHetncLuq4B/5ztm7KBS9DabNbivdxAK zp8lUudSumyDcz/jZGoFkL7dFyC/PvA= X-Google-Smtp-Source: AGHT+IEDx2fXN1mZpC4wdLenC0gEZqGHeyYGeZi/NHNboFx849UKp0hRFulm5OGynaHR+kwHxlTzuAC9hXU= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a0d:d785:0:b0:59b:c811:a709 with SMTP id z127-20020a0dd785000000b0059bc811a709mr3270ywd.0.1698939893755; Thu, 02 Nov 2023 08:44:53 -0700 (PDT) Date: Thu, 2 Nov 2023 08:44:52 -0700 In-Reply-To: <496b78bb-ad12-4eed-a62c-8c2fd725ec61@redhat.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231027182217.3615211-1-seanjc@google.com> <20231027182217.3615211-10-seanjc@google.com> <482bfea6f54ea1bb7d1ad75e03541d0ba0e5be6f.camel@intel.com> <64e3764e36ba7a00d94cc7db1dea1ef06b620aaf.camel@intel.com> <32cb71700aedcbd1f65276cf44a601760ffc364b.camel@intel.com> <496b78bb-ad12-4eed-a62c-8c2fd725ec61@redhat.com> Message-ID: Subject: Re: [PATCH v13 09/35] KVM: Add KVM_EXIT_MEMORY_FAULT exit to report faults to userspace From: Sean Christopherson To: Paolo Bonzini Cc: Kai Huang , Xiaoyao Li , "kvm-riscv@lists.infradead.org" , "mic@digikod.net" , "liam.merwick@oracle.com" , "kvm@vger.kernel.org" , Isaku Yamahata , "viro@zeniv.linux.org.uk" , "kirill.shutemov@linux.intel.com" , "david@redhat.com" , "linux-mips@vger.kernel.org" , "amoorthy@google.com" , "linuxppc-dev@lists.ozlabs.org" , "tabba@google.com" , "kvmarm@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "oliver.upton@linux.dev" , "michael.roth@amd.com" , "chao.p.peng@linux.intel.com" , "palmer@dabbelt.com" , "chenhuacai@kernel.org" , "aou@eecs.berkeley.edu" , "mpe@ellerman.id.au" , Vishal Annapurve , "vbabka@suse.cz" , "mail@maciej.szmigiero.name" , "linux-riscv@lists.infradead.org" , "maz@kernel.org" , "willy@infradead.org" , "dmatlack@google.com" , "anup@brainfault.org" , "yu.c.zhang@linux.intel.com" , Yilun Xu , "qperret@google.com" , "brauner@kernel.org" , "isaku.yamahata@gmail.com" , "ackerleytng@google.com" , "jarkko@kernel.org" , "paul.walmsley@sifive.com" , "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" , Wei W Wang , "akpm@linux-foundation.org" Content-Type: text/plain; charset="us-ascii" On Thu, Nov 02, 2023, Paolo Bonzini wrote: > On 11/2/23 10:35, Huang, Kai wrote: > > IIUC KVM can already handle the case of poisoned > > page by sending signal to user app: > > > > static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, struct > > kvm_page_fault *fault) { > > ... > > > > if (fault->pfn == KVM_PFN_ERR_HWPOISON) { > > kvm_send_hwpoison_signal(fault->slot, fault->gfn); No, this doesn't work, because that signals the host virtual address unsigned long hva = gfn_to_hva_memslot(slot, gfn); send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva, PAGE_SHIFT, current); which is the *shared* page. > > return RET_PF_RETRY; > > } > > } > > EHWPOISON is not implemented by this series, so it should be left out of the > documentation. EHWPOISON *is* implemented. kvm_gmem_get_pfn() returns -EWPOISON as appropriate, and kvm_faultin_pfn() returns that directly without going through kvm_handle_error_pfn(). kvm_faultin_pfn_private() | |-> kvm_gmem_get_pfn() | |-> if (folio_test_hwpoison(folio)) { r = -EHWPOISON; goto out_unlock; } | |-> r = kvm_gmem_get_pfn(vcpu->kvm, fault->slot, fault->gfn, &fault->pfn, &max_order); if (r) { kvm_mmu_prepare_memory_fault_exit(vcpu, fault); return r; } | |-> ret = __kvm_faultin_pfn(vcpu, fault); if (ret != RET_PF_CONTINUE) return ret; if (unlikely(is_error_pfn(fault->pfn))) return kvm_handle_error_pfn(vcpu, fault);