From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 07C8E125D5 for ; Wed, 15 Nov 2023 10:42:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LQh2Kzhn" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 74C5BC2 for ; Wed, 15 Nov 2023 02:42:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700044955; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=DBtY48dW5FDAaMIcFUThoBhO+9fnXcfuCT2ZrkWuo/I=; b=LQh2Kzhn5dera8Dwca87fEWnTpsgIfc+RAaQ0Bqm0evyDFp2lR1cp184D+VW2ghK0g3k4D UvuasTMUAeiaLfe8JJJFirGrOzq1M1nGtKuVN5IVuaEusbQ9tfLZ1fyJrm4tGy+xVVQcIC mCBgx5alx7t3ZKIfhDhFG0z111MN6No= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-690-Azq19YFMPAeZP8aQ4aJB_A-1; Wed, 15 Nov 2023 05:42:32 -0500 X-MC-Unique: Azq19YFMPAeZP8aQ4aJB_A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 82893811E7B; Wed, 15 Nov 2023 10:42:31 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.144]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E9C14C2E120; Wed, 15 Nov 2023 10:42:26 +0000 (UTC) Date: Wed, 15 Nov 2023 10:42:24 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Xiaoyao Li Cc: Paolo Bonzini , David Hildenbrand , Igor Mammedov , "Michael S . Tsirkin" , Marcel Apfelbaum , Richard Henderson , Peter Xu , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Cornelia Huck , Eric Blake , Markus Armbruster , Marcelo Tosatti , qemu-devel@nongnu.org, kvm@vger.kernel.org, Michael Roth , Sean Christopherson , Claudio Fontana , Gerd Hoffmann , Isaku Yamahata , Chenyi Qiang Subject: Re: [PATCH v3 10/70] kvm: handle KVM_EXIT_MEMORY_FAULT Message-ID: Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20231115071519.2864957-1-xiaoyao.li@intel.com> <20231115071519.2864957-11-xiaoyao.li@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231115071519.2864957-11-xiaoyao.li@intel.com> User-Agent: Mutt/2.2.10 (2023-03-25) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 On Wed, Nov 15, 2023 at 02:14:19AM -0500, Xiaoyao Li wrote: > From: Chao Peng > > Currently only KVM_MEMORY_EXIT_FLAG_PRIVATE in flags is valid when > KVM_EXIT_MEMORY_FAULT happens. It indicates userspace needs to do > the memory conversion on the RAMBlock to turn the memory into desired > attribute, i.e., private/shared. > > Note, KVM_EXIT_MEMORY_FAULT makes sense only when the RAMBlock has > guest_memfd memory backend. > > Note, KVM_EXIT_MEMORY_FAULT returns with -EFAULT, so special handling is > added. > > Signed-off-by: Chao Peng > Co-developed-by: Xiaoyao Li > Signed-off-by: Xiaoyao Li > --- > accel/kvm/kvm-all.c | 76 +++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 66 insertions(+), 10 deletions(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index 76e2404d54d2..58abbcb6926e 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -2902,6 +2902,50 @@ static void kvm_eat_signals(CPUState *cpu) > } while (sigismember(&chkset, SIG_IPI)); > } > > +static int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) > +{ > + MemoryRegionSection section; > + ram_addr_t offset; > + RAMBlock *rb; > + void *addr; > + int ret = -1; > + > + section = memory_region_find(get_system_memory(), start, size); > + if (!section.mr) { > + return ret; > + } > + > + if (memory_region_has_guest_memfd(section.mr)) { > + if (to_private) { > + ret = kvm_set_memory_attributes_private(start, size); > + } else { > + ret = kvm_set_memory_attributes_shared(start, size); > + } > + > + if (ret) { > + memory_region_unref(section.mr); > + return ret; > + } > + > + addr = memory_region_get_ram_ptr(section.mr) + > + section.offset_within_region; > + rb = qemu_ram_block_from_host(addr, false, &offset); > + /* > + * With KVM_SET_MEMORY_ATTRIBUTES by kvm_set_memory_attributes(), > + * operation on underlying file descriptor is only for releasing > + * unnecessary pages. > + */ > + ram_block_convert_range(rb, offset, size, to_private); > + } else { > + warn_report("Convert non guest_memfd backed memory region " > + "(0x%"HWADDR_PRIx" ,+ 0x%"HWADDR_PRIx") to %s", > + start, size, to_private ? "private" : "shared"); Again, if you're returning '-1' to indicate error, then using warn_report is wrong, it should be error_report. warn_report is for when you return success, indicating the problem was non-fatal. > + } > + > + memory_region_unref(section.mr); > + return ret; > +} > + > int kvm_cpu_exec(CPUState *cpu) > { > struct kvm_run *run = cpu->kvm_run; > @@ -2969,18 +3013,20 @@ int kvm_cpu_exec(CPUState *cpu) > ret = EXCP_INTERRUPT; > break; > } > - fprintf(stderr, "error: kvm run failed %s\n", > - strerror(-run_ret)); > + if (!(run_ret == -EFAULT && run->exit_reason == KVM_EXIT_MEMORY_FAULT)) { > + fprintf(stderr, "error: kvm run failed %s\n", > + strerror(-run_ret)); > #ifdef TARGET_PPC > - if (run_ret == -EBUSY) { > - fprintf(stderr, > - "This is probably because your SMT is enabled.\n" > - "VCPU can only run on primary threads with all " > - "secondary threads offline.\n"); > - } > + if (run_ret == -EBUSY) { > + fprintf(stderr, > + "This is probably because your SMT is enabled.\n" > + "VCPU can only run on primary threads with all " > + "secondary threads offline.\n"); > + } > #endif > - ret = -1; > - break; > + ret = -1; > + break; > + } > } > > trace_kvm_run_exit(cpu->cpu_index, run->exit_reason); > @@ -3067,6 +3113,16 @@ int kvm_cpu_exec(CPUState *cpu) > break; > } > break; > + case KVM_EXIT_MEMORY_FAULT: > + if (run->memory_fault.flags & ~KVM_MEMORY_EXIT_FLAG_PRIVATE) { > + error_report("KVM_EXIT_MEMORY_FAULT: Unknown flag 0x%" PRIx64, > + (uint64_t)run->memory_fault.flags); > + ret = -1; > + break; > + } > + ret = kvm_convert_memory(run->memory_fault.gpa, run->memory_fault.size, > + run->memory_fault.flags & KVM_MEMORY_EXIT_FLAG_PRIVATE); > + break; > default: > DPRINTF("kvm_arch_handle_exit\n"); > ret = kvm_arch_handle_exit(cpu, run); > -- > 2.34.1 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|