From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Ehrhardt Subject: Re: [PATCH] kvm: work around inability of older kvm modules to destroy memory regions Date: Wed, 17 Dec 2008 14:09:28 +0100 Message-ID: <4948FA08.8010505@linux.vnet.ibm.com> References: <20081209161057.DC28A25006D@cleopatra.tlv.redhat.com> <493FCD5A.7010308@linux.vnet.ibm.com> <4948EFEC.2020407@redhat.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------050007070903020804000907" Cc: kvm , Hollis Blanchard , Carsten Otte , Christian Borntraeger To: Avi Kivity Return-path: Received: from mtagate6.de.ibm.com ([195.212.29.155]:47486 "EHLO mtagate6.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751009AbYLQNKg (ORCPT ); Wed, 17 Dec 2008 08:10:36 -0500 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate6.de.ibm.com (8.13.8/8.13.8) with ESMTP id mBHD9X8k478182 for ; Wed, 17 Dec 2008 13:09:34 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mBHD9Xek2691088 for ; Wed, 17 Dec 2008 14:09:33 +0100 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mBHD9Wsg006484 for ; Wed, 17 Dec 2008 14:09:33 +0100 In-Reply-To: <4948EFEC.2020407@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------050007070903020804000907 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Avi Kivity wrote: > Christian Ehrhardt wrote: >> Hi, this patch breaks all non x86 architectures as >> libkvm/libkvm-x86.c has the only implementation of the alias >> functionality. >> Until now only qemu-kvm-x86 has called that functions, but since this >> patch the generic qemu-kvm.c calls them which leads to unresolved >> symbols for powerpc, s390 and surely ia64 too. >> >> Well we could insert stubs for these call, but when looking on the >> kernel side x86 is also the only implementer of the >> KVM_SET_MEMORY_ALIAS ioctl. Until more arch support that there is no >> reason to create these functions for non-x86 in libkvm. Also the >> assumptions which addresses must be aliased base on hardware specific >> assumptions e.g. vga card -> arch specific too. >> >> For now I hold a no-op stub in my private queue to test powerpc, but >> eventually this mechanism should be arch dependent and this >> implementation x86 only. >> Avi could you modify your patch to work for the other arch's too ? > > Your band aid should be fine. Yes, it's ugly, but this will be in > flux as we merge with upstream qemu. Please resend it with a signoff. > still ugly, but in a proper patch style now :-) -- Grüsse / regards, Christian Ehrhardt IBM Linux Technology Center, Open Virtualization --------------050007070903020804000907 Content-Type: text/x-diff; name="memory-aliases.diff" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="memory-aliases.diff" Subject: [PATCH] kvm-userspace: guard destroy memory regions to x86 only From: Christian Ehrhardt Some parts of the changes made were arch specific e..g vga mem. This is a quick, but ugly workaround until a real arch split is found. Signed-off-by: Christian Ehrhardt --- [diffstat] qemu-kvm.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) [diff] diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c --- a/qemu/qemu-kvm.c +++ b/qemu/qemu-kvm.c @@ -766,7 +766,9 @@ int kvm_qemu_init() return 0; } +#ifdef TARGET_I386 static int destroy_region_works = 0; +#endif int kvm_qemu_create_context(void) { @@ -784,7 +786,9 @@ int kvm_qemu_create_context(void) r = kvm_arch_qemu_create_context(); if(r <0) kvm_qemu_destroy(); +#ifdef TARGET_I386 destroy_region_works = kvm_destroy_memory_region_works(kvm_context); +#endif return 0; } @@ -793,6 +797,7 @@ void kvm_qemu_destroy(void) kvm_finalize(kvm_context); } +#ifdef TARGET_I386 static int must_use_aliases_source(target_phys_addr_t addr) { if (destroy_region_works) @@ -849,6 +854,7 @@ static void drop_mapping(target_phys_add if (p) *p = mappings[--nr_mappings]; } +#endif void kvm_cpu_register_physical_memory(target_phys_addr_t start_addr, unsigned long size, @@ -856,17 +862,21 @@ void kvm_cpu_register_physical_memory(ta { int r = 0; unsigned long area_flags = phys_offset & ~TARGET_PAGE_MASK; +#ifdef TARGET_I386 struct mapping *p; +#endif phys_offset &= ~IO_MEM_ROM; if (area_flags == IO_MEM_UNASSIGNED) { +#ifdef TARGET_I386 if (must_use_aliases_source(start_addr)) { kvm_destroy_memory_alias(kvm_context, start_addr); return; } if (must_use_aliases_target(start_addr)) return; +#endif kvm_unregister_memory_area(kvm_context, start_addr, size); return; } @@ -878,6 +888,7 @@ void kvm_cpu_register_physical_memory(ta if (area_flags >= TLB_MMIO) return; +#ifdef TARGET_I386 if (must_use_aliases_source(start_addr)) { p = find_ram_mapping(phys_offset); if (p) { @@ -886,6 +897,7 @@ void kvm_cpu_register_physical_memory(ta } return; } +#endif r = kvm_register_phys_mem(kvm_context, start_addr, phys_ram_base + phys_offset, @@ -895,11 +907,13 @@ void kvm_cpu_register_physical_memory(ta exit(1); } +#ifdef TARGET_I386 drop_mapping(start_addr); p = &mappings[nr_mappings++]; p->phys = start_addr; p->ram = phys_offset; p->len = size; +#endif return; } @@ -1068,8 +1082,10 @@ void kvm_qemu_log_memory(target_phys_add if (log) kvm_dirty_pages_log_enable_slot(kvm_context, start, size); else { +#ifdef TARGET_I386 if (must_use_aliases_target(start)) return; +#endif kvm_dirty_pages_log_disable_slot(kvm_context, start, size); } } @@ -1157,8 +1173,10 @@ void kvm_physical_sync_dirty_bitmap(targ { void *buf; +#ifdef TARGET_I386 if (must_use_aliases_source(start_addr)) return; +#endif buf = qemu_malloc((end_addr - start_addr) / 8 + 2); kvm_get_dirty_pages_range(kvm_context, start_addr, end_addr - start_addr, @@ -1168,21 +1186,21 @@ void kvm_physical_sync_dirty_bitmap(targ int kvm_log_start(target_phys_addr_t phys_addr, target_phys_addr_t len) { -#ifndef TARGET_IA64 +#ifdef TARGET_I386 if (must_use_aliases_source(phys_addr)) return 0; +#endif kvm_qemu_log_memory(phys_addr, len, 1); -#endif return 0; } int kvm_log_stop(target_phys_addr_t phys_addr, target_phys_addr_t len) { -#ifndef TARGET_IA64 +#ifdef TARGET_I386 if (must_use_aliases_source(phys_addr)) return 0; +#endif kvm_qemu_log_memory(phys_addr, len, 0); -#endif return 0; } --------------050007070903020804000907--