From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F394BC54E58 for ; Tue, 26 Mar 2024 08:54:58 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rp2ZF-0001Qz-Nw; Tue, 26 Mar 2024 04:54:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rp2ZD-0001QX-6X for qemu-devel@nongnu.org; Tue, 26 Mar 2024 04:53:59 -0400 Received: from mgamail.intel.com ([192.198.163.10]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rp2ZA-0003Y3-9x for qemu-devel@nongnu.org; Tue, 26 Mar 2024 04:53:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1711443236; x=1742979236; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=o6CKEXzuWXuaqzz3HHRs/+rhhgDFmVWiIvroEDORB3A=; b=Xh9a8OxMapI4TnZd0Ecu5qM+L/9vQ0xkOCHtrvmsXoI0qE9XBhd94355 feLdFmF0BbdaC0fAz8Kfudd293sd8zGYe1RXQzFWR/6VN7OfyiFjYQfIh rmwI7H6V8xauWUXOOu7Rn3eMorrkwxX0GNevJ9Andezwbo0tK9Cw0zv5j +s5UVfvXveVL0PNm9Q8e+23g96LLIPgfNNimO46d73Pa1ORhNB0ZlPEe2 Ai5s6Y9JY6dA69tG3kZlHN0saj4FHUvN1CGHzlvEEKV9s85CL/B3DVYaw sNhA8ALCnT3ragXVukM2haXpF3wUbLoHOt942RtGAXD9X3cnJE7svISRH g==; X-IronPort-AV: E=McAfee;i="6600,9927,11024"; a="17873534" X-IronPort-AV: E=Sophos;i="6.07,155,1708416000"; d="scan'208";a="17873534" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Mar 2024 01:53:52 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,155,1708416000"; d="scan'208";a="16285527" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.224.7]) ([10.124.224.7]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Mar 2024 01:53:51 -0700 Message-ID: <52df5a0e-6812-41ae-a5c6-7d403b33f84a@intel.com> Date: Tue, 26 Mar 2024 16:53:47 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 25/26] kvm: handle KVM_EXIT_MEMORY_FAULT To: Paolo Bonzini , qemu-devel@nongnu.org Cc: michael.roth@amd.com, david@redhat.com References: <20240322181116.1228416-1-pbonzini@redhat.com> <20240322181116.1228416-26-pbonzini@redhat.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20240322181116.1228416-26-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=192.198.163.10; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.com X-Spam_score_int: -11 X-Spam_score: -1.2 X-Spam_bar: - X-Spam_report: (-1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.065, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 3/23/2024 2:11 AM, Paolo Bonzini wrote: > From: Chao Peng > > When geeting KVM_EXIT_MEMORY_FAULT exit, it indicates userspace needs to typo: /s/geeting/getting > do the memory conversion on the RAMBlock to turn the memory into desired > attribute, i.e., private/shared. > > Currently only KVM_MEMORY_EXIT_FLAG_PRIVATE in flags is valid when > KVM_EXIT_MEMORY_FAULT happens. > > 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. > > When page is converted from shared to private, the original shared > memory can be discarded via ram_block_discard_range(). Note, shared > memory can be discarded only when it's not back'ed by hugetlb because > hugetlb is supposed to be pre-allocated and no need for discarding. > > Signed-off-by: Chao Peng > Co-developed-by: Xiaoyao Li > Signed-off-by: Xiaoyao Li > > Message-ID: <20240320083945.991426-13-michael.roth@amd.com> > Signed-off-by: Paolo Bonzini > --- > include/sysemu/kvm.h | 2 + > accel/kvm/kvm-all.c | 99 +++++++++++++++++++++++++++++++++++++----- > accel/kvm/trace-events | 2 + > 3 files changed, 93 insertions(+), 10 deletions(-) > > diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h > index 2cb31925091..698f1640fe2 100644 > --- a/include/sysemu/kvm.h > +++ b/include/sysemu/kvm.h > @@ -541,4 +541,6 @@ int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp); > > int kvm_set_memory_attributes_private(hwaddr start, hwaddr size); > int kvm_set_memory_attributes_shared(hwaddr start, hwaddr size); > + > +int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private); > #endif > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index 56b17cbd8aa..afd7f992e39 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -2893,6 +2893,70 @@ static void kvm_eat_signals(CPUState *cpu) > } while (sigismember(&chkset, SIG_IPI)); > } > > +int kvm_convert_memory(hwaddr start, hwaddr size, bool to_private) > +{ > + MemoryRegionSection section; > + ram_addr_t offset; > + MemoryRegion *mr; > + RAMBlock *rb; > + void *addr; > + int ret = -1; > + > + trace_kvm_convert_memory(start, size, to_private ? "shared_to_private" : "private_to_shared"); > + > + if (!QEMU_PTR_IS_ALIGNED(start, qemu_real_host_page_size()) || > + !QEMU_PTR_IS_ALIGNED(size, qemu_real_host_page_size())) { > + return -1; > + } > + > + if (!size) { > + return -1; > + } > + > + section = memory_region_find(get_system_memory(), start, size); > + mr = section.mr; > + if (!mr) { > + return -1; > + } > + > + if (!memory_region_has_guest_memfd(mr)) { > + error_report("Converting non guest_memfd backed memory region " > + "(0x%"HWADDR_PRIx" ,+ 0x%"HWADDR_PRIx") to %s", > + start, size, to_private ? "private" : "shared"); > + ret = -1; No need for it. ret is initialized as -1 at the function start. > + goto out_unref; > + } > + > + if (to_private) { > + ret = kvm_set_memory_attributes_private(start, size); > + } else { > + ret = kvm_set_memory_attributes_shared(start, size); > + } > + if (ret) { > + goto out_unref; > + } > + > + addr = memory_region_get_ram_ptr(mr) + section.offset_within_region; > + rb = qemu_ram_block_from_host(addr, false, &offset); > + > + if (to_private) { > + if (rb->page_size == qemu_real_host_page_size()) { > + /* > + * shared memory is back'ed by hugetlb, which is supposed to be Please fix the bad comment indentation for me, as well as the extra space before 'hugetlb' > + * pre-allocated and doesn't need to be discarded > + */ > + goto out_unref; > + } > + ret = ram_block_discard_range(rb, offset, size); > + } else { > + ret = ram_block_discard_guest_memfd_range(rb, offset, size); > + } > + > +out_unref: > + memory_region_unref(section.mr); > + return ret; > +} > + > int kvm_cpu_exec(CPUState *cpu) > { > struct kvm_run *run = cpu->kvm_run; > @@ -2960,18 +3024,20 @@ 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); > @@ -3054,6 +3120,19 @@ int kvm_cpu_exec(CPUState *cpu) > break; > } > break; > + case KVM_EXIT_MEMORY_FAULT: > + trace_kvm_memory_fault(run->memory_fault.gpa, > + run->memory_fault.size, > + run->memory_fault.flags); > + 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: > ret = kvm_arch_handle_exit(cpu, run); > break; > diff --git a/accel/kvm/trace-events b/accel/kvm/trace-events > index e8c52cb9e7a..681ccb667d6 100644 > --- a/accel/kvm/trace-events > +++ b/accel/kvm/trace-events > @@ -31,3 +31,5 @@ kvm_cpu_exec(void) "" > kvm_interrupt_exit_request(void) "" > kvm_io_window_exit(void) "" > kvm_run_exit_system_event(int cpu_index, uint32_t event_type) "cpu_index %d, system_even_type %"PRIu32 > +kvm_convert_memory(uint64_t start, uint64_t size, const char *msg) "start 0x%" PRIx64 " size 0x%" PRIx64 " %s" > +kvm_memory_fault(uint64_t start, uint64_t size, uint64_t flags) "start 0x%" PRIx64 " size 0x%" PRIx64 " flags 0x%" PRIx64