From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34632) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WPYuS-0005BV-7W for qemu-devel@nongnu.org; Mon, 17 Mar 2014 10:53:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WPYuL-0007Az-Uv for qemu-devel@nongnu.org; Mon, 17 Mar 2014 10:53:00 -0400 Received: from omzsmtpe04.verizonbusiness.com ([199.249.25.207]:24493) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WPYuL-0007As-Mc for qemu-devel@nongnu.org; Mon, 17 Mar 2014 10:52:53 -0400 From: Don Slutz Message-ID: <53270C42.60804@terremark.com> Date: Mon, 17 Mar 2014 10:52:50 -0400 MIME-Version: 1.0 References: <1394553546-6581-1-git-send-email-dslutz@verizon.com> <1394553546-6581-5-git-send-email-dslutz@verizon.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 4/4] xen-all: Pass max_ram_below_4g to xen_hvm_init. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefano Stabellini , Don Slutz Cc: xen-devel@lists.xensource.com, qemu-devel@nongnu.org, Anthony Liguori , "Michael S. Tsirkin" On 03/16/14 12:10, Stefano Stabellini wrote: > On Tue, 11 Mar 2014, Don Slutz wrote: >> This is the xen part of "pc & q35: Add new object pc-memory-layout." >> >> Signed-off-by: Don Slutz >> --- >> hw/i386/pc_piix.c | 4 ++-- >> hw/i386/pc_q35.c | 4 ++-- >> include/hw/xen/xen.h | 4 ++-- >> xen-all.c | 41 ++++++++++++++++++++++------------------- >> xen-stub.c | 4 ++-- >> 5 files changed, 30 insertions(+), 27 deletions(-) >> >> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c >> index 964ea33..691fc5d 100644 >> --- a/hw/i386/pc_piix.c >> +++ b/hw/i386/pc_piix.c >> @@ -131,8 +131,8 @@ static void pc_init1(QEMUMachineInitArgs *args, >> below_4g_mem_size = args->ram_size; >> } >> >> - if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size, >> - &ram_memory) != 0) { >> + if (xen_enabled() && xen_hvm_init(max_ram_below_4g, &below_4g_mem_size, >> + &above_4g_mem_size, &ram_memory) != 0) { >> fprintf(stderr, "xen hardware virtual machine initialisation failed\n"); >> exit(1); >> } >> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c >> index c95e6e2..8e1c417 100644 >> --- a/hw/i386/pc_q35.c >> +++ b/hw/i386/pc_q35.c >> @@ -120,8 +120,8 @@ static void pc_q35_init(QEMUMachineInitArgs *args) >> below_4g_mem_size = args->ram_size; >> } >> >> - if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size, >> - &ram_memory) != 0) { >> + if (xen_enabled() && xen_hvm_init(max_ram_below_4g, &below_4g_mem_size, >> + &above_4g_mem_size, &ram_memory) != 0) { >> fprintf(stderr, "xen hardware virtual machine initialisation failed\n"); >> exit(1); >> } >> diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h >> index 0769db2..fda559a 100644 >> --- a/include/hw/xen/xen.h >> +++ b/include/hw/xen/xen.h >> @@ -41,8 +41,8 @@ int xen_init(QEMUMachine *machine); >> void xenstore_store_pv_console_info(int i, struct CharDriverState *chr); >> >> #if defined(NEED_CPU_H) && !defined(CONFIG_USER_ONLY) >> -int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size, >> - MemoryRegion **ram_memory); >> +int xen_hvm_init(ram_addr_t max_ram_below_4g, ram_addr_t *below_4g_mem_size, >> + ram_addr_t *above_4g_mem_size, MemoryRegion **ram_memory); >> void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size, >> struct MemoryRegion *mr); >> void xen_modified_memory(ram_addr_t start, ram_addr_t length); >> diff --git a/xen-all.c b/xen-all.c >> index c64300c..48ba335 100644 >> --- a/xen-all.c >> +++ b/xen-all.c >> @@ -155,32 +155,34 @@ qemu_irq *xen_interrupt_controller_init(void) >> >> /* Memory Ops */ >> >> -static void xen_ram_init(ram_addr_t *below_4g_mem_size, >> +static void xen_ram_init(ram_addr_t ram_size, ram_addr_t max_ram_below_4g, >> + ram_addr_t *below_4g_mem_size, >> ram_addr_t *above_4g_mem_size, >> - ram_addr_t ram_size, MemoryRegion **ram_memory_p) >> + MemoryRegion **ram_memory_p) >> { >> MemoryRegion *sysmem = get_system_memory(); >> ram_addr_t block_len; >> >> - block_len = ram_size; >> - if (ram_size >= HVM_BELOW_4G_RAM_END) { >> - /* Xen does not allocate the memory continuously, and keep a hole at >> - * HVM_BELOW_4G_MMIO_START of HVM_BELOW_4G_MMIO_LENGTH >> - */ >> - block_len += HVM_BELOW_4G_MMIO_LENGTH; >> + if (!max_ram_below_4g) { >> + if (ram_size >= HVM_BELOW_4G_RAM_END) { >> + *above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END; >> + *below_4g_mem_size = HVM_BELOW_4G_RAM_END; >> + } else { >> + *above_4g_mem_size = 0; >> + *below_4g_mem_size = ram_size; >> + } >> + } > Instead of treating max_ram_below_4g as a special case, couldn't > initialize it to HVM_BELOW_4G_RAM_END? Since max_ram_below_4g is used and initialize in normal QEMU code where HVM_BELOW_4G_RAM_END is not defined, I do not see how to do this outside of this routine without adding a new routine for this. > We could consider HVM_BELOW_4G_RAM_END as the upper bound of > max_ram_below_4g. Yes. Currently the only limit on max_ram_below_4g is 4G. I am on the fence on this. I think there are valid values > HVM_BELOW_4G_RAM_END, but not clear they need to be supported. > I would just change the code to: > > if (ram_size >= max_ram_below_4g) { > above_4g_mem_size = ram_size - max_ram_below_4g; > below_4g_mem_size = max_ram_below_4g; > } else { > below_4g_mem_size = ram_size; > } > This is the code that is in patch #3 in the normal QEMU path but using the variable lowmem so that xen can know if max_ram_below_4g was set to non-zero. The issue that I am looking at handling here is the case of an older xen (does not know about max_ram_below_4g) and the newer QEMU, where xen expects QEMUs memory layout to change to HVM_BELOW_4G_RAM_END. Because of this (QEMU is doing the right thing if max_ram_below_4g is non-zero) is why I coded it as only when max_ram_below_4g is zero, the xen default is not the same as QEMU. -Don Slutz >> + if (!*above_4g_mem_size) { >> + block_len = ram_size; >> + } else { >> + /* Xen does not allocate the memory continuously, and keep a hole of >> + * of the size computed above or passed in. */ >> + block_len = (1ULL << 32) + *above_4g_mem_size; >> } >> memory_region_init_ram(&ram_memory, NULL, "xen.ram", block_len); >> *ram_memory_p = &ram_memory; >> vmstate_register_ram_global(&ram_memory); >> >> - if (ram_size >= HVM_BELOW_4G_RAM_END) { >> - *above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END; >> - *below_4g_mem_size = HVM_BELOW_4G_RAM_END; >> - } else { >> - *above_4g_mem_size = 0; >> - *below_4g_mem_size = ram_size; >> - } >> - >> memory_region_init_alias(&ram_640k, NULL, "xen.ram.640k", >> &ram_memory, 0, 0xa0000); >> memory_region_add_subregion(sysmem, 0, &ram_640k); >> @@ -1069,8 +1071,8 @@ static void xen_wakeup_notifier(Notifier *notifier, void *data) >> xc_set_hvm_param(xen_xc, xen_domid, HVM_PARAM_ACPI_S_STATE, 0); >> } >> >> -int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size, >> - MemoryRegion **ram_memory) >> +int xen_hvm_init(ram_addr_t max_ram_below_4g, ram_addr_t *below_4g_mem_size, >> + ram_addr_t *above_4g_mem_size, MemoryRegion **ram_memory) >> { >> int i, rc; >> unsigned long ioreq_pfn; >> @@ -1148,7 +1150,8 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size, >> >> /* Init RAM management */ >> xen_map_cache_init(xen_phys_offset_to_gaddr, state); >> - xen_ram_init(below_4g_mem_size, above_4g_mem_size, ram_size, ram_memory); >> + xen_ram_init(ram_size, max_ram_below_4g, below_4g_mem_size, >> + above_4g_mem_size, ram_memory); >> >> qemu_add_vm_change_state_handler(xen_hvm_change_state_handler, state); >> >> diff --git a/xen-stub.c b/xen-stub.c >> index 0302dff..dd317a5 100644 >> --- a/xen-stub.c >> +++ b/xen-stub.c >> @@ -64,8 +64,8 @@ void xen_modified_memory(ram_addr_t start, ram_addr_t length) >> { >> } >> >> -int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size, >> - MemoryRegion **ram_memory) >> +int xen_hvm_init(ram_addr_t max_ram_below_4g, ram_addr_t *below_4g_mem_size, >> + ram_addr_t *above_4g_mem_size, MemoryRegion **ram_memory) >> { >> return 0; >> } >> -- >> 1.8.4 >>