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Mon, 29 Jul 2019 17:53:21 +0000 (UTC) Received: from work-vm (ovpn-117-222.ams2.redhat.com [10.36.117.222]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F3AAE600F8; Mon, 29 Jul 2019 17:53:17 +0000 (UTC) Date: Mon, 29 Jul 2019 18:53:15 +0100 From: "Dr. David Alan Gilbert" To: Igor Mammedov Message-ID: <20190729175315.GK2756@work-vm> References: <20190729145229.4333-1-imammedo@redhat.com> <20190729145229.4333-2-imammedo@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190729145229.4333-2-imammedo@redhat.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Mon, 29 Jul 2019 17:53:21 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH RFC 1/2] memory: make MemoryRegion alias migratable X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, qemu-s390x@nongnu.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Igor Mammedov (imammedo@redhat.com) wrote: > use qemu_ram_alloc_from_ptr() to create aliased RAMBlock > to the part of original memory region. > > Signed-off-by: Igor Mammedov > --- > exec.c | 7 ++++--- > memory.c | 5 +++++ > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/exec.c b/exec.c > index 3e78de3b8f..daef0cd54f 100644 > --- a/exec.c > +++ b/exec.c > @@ -2313,7 +2313,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared) > new_block->used_length, > DIRTY_CLIENTS_ALL); > > - if (new_block->host) { > + if (new_block->host && !new_block->mr->alias) { > qemu_ram_setup_dump(new_block->host, new_block->max_length); > qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_HUGEPAGE); > /* MADV_DONTFORK is also needed by KVM in absence of synchronous MMU */ > @@ -2671,7 +2671,8 @@ RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset, > > rcu_read_lock(); > block = atomic_rcu_read(&ram_list.mru_block); > - if (block && block->host && host - block->host < block->max_length) { > + if (block && !block->mr->alias && block->host && > + host - block->host < block->max_length) { > goto found; > } > > @@ -2680,7 +2681,7 @@ RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset, > if (block->host == NULL) { > continue; > } > - if (host - block->host < block->max_length) { > + if (!block->mr->alias && host - block->host < block->max_length) { > goto found; > } > } > diff --git a/memory.c b/memory.c > index 5d8c9a9234..d710c17a26 100644 > --- a/memory.c > +++ b/memory.c > @@ -1678,6 +1678,11 @@ void memory_region_init_alias(MemoryRegion *mr, > memory_region_init(mr, owner, name, size); > mr->alias = orig; > mr->alias_offset = offset; > + if (orig->ram_block && size) { > + mr->ram_block = qemu_ram_alloc_from_ptr(size, > + orig->ram_block->host + offset, > + mr, &error_fatal); > + } > } Doesn't this cause new memory regions to be created in other existing machines, e.g. x86's mem-smram, or the various PCI vga hacks? Dave > > void memory_region_init_rom_nomigrate(MemoryRegion *mr, > -- > 2.18.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK