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From: Igor Mammedov <imammedo@redhat.com>
To: Helge Deller <deller@gmx.de>
Cc: "Sven Schnelle" <svens@stackframe.org>,
	"Philippe Mathieu-Daudé" <philmd@redhat.com>,
	qemu-devel@nongnu.org
Subject: Re: [PATCH v2] hppa: allow max ram size upto 4Gb
Date: Tue, 7 Jan 2020 16:17:29 +0100	[thread overview]
Message-ID: <20200107161729.09d84dc4@redhat.com> (raw)
In-Reply-To: <4272cf03-cd8a-3a29-b3c2-65788a60b50a@gmx.de>

On Tue, 7 Jan 2020 12:53:32 +0100
Helge Deller <deller@gmx.de> wrote:

Even though I disagree and it would waste ~256Mb 4Gb of RAM,
I think I should be able to replace #43 with
  "hppa: allow max ram size upto 4Gb"
as it still removes fix up at mapped address space level,
removes fix up of global ram_size variable and adds max size check,

which lets hppa board get out of the way of re-factoring
generic RAM allocation and making what board does with
provided RAM its own business.

> On 07.01.20 12:21, Igor Mammedov wrote:
> > On Mon, 6 Jan 2020 18:03:49 +0100  
> >> So, I'd suggest to drop your wrong patch #43.  
> > As you noted in your first reply, patch is correct.  
> 
> You probably got me wrong.
whichever way I read it
https://www.mail-archive.com/qemu-devel@nongnu.org/msg667855.html
states user convenience as a reason.

> Your patch #43 is wrong, and your fixup patch to some degree reverts it back again.
>
> 
> In patch #43 you error out and stop, which real hardware wouldn't do.
> Real hardware simply ignores the memory which wouldn't be used.
> > All it's doing is validating user input versus RAM size
> > actually supported by the current code, telling user> current supported limit and enforcing it.  
> 
> Real hardware would not tell user.
>
> > I agree it's inconvenience for the users since they
> > won't be able to specify non-sense values and still
> > get board running, but that's clear user error and
> > should be corrected on user side and not by QEMU
> > magically masking wrong CLI values.  
> 
> I disagree.
> Everything worked as expected before, but with *your* change now people
> might need to modify their CLI.
> 4GB is a valid amount of memory which can be plugged into
> the virtual and physical machine.
> It's not magic, it's how the architecture works and you changed it.
>
> > Since it could be fixed on user side, I care less
> > about user convenience when it comes to correctness
> > and unified code.  
> 
> IMHO, you should care about that the emulation works the same
> way as physical machine. 

As for correctness wrt real hardware questions are:
 * is one able to stuff hardware with unsupported 4Gb or more DIMMs,
   will system even work?
 * what real hardware does with top 256Gb of 4Gb RAM if present?
   Is it addressable/accessible in some way by CPUs or devices?
 * how does real firmware discovers amount of installed RAM

[...]



  reply	other threads:[~2020-01-07 15:35 UTC|newest]

Thread overview: 148+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-31 13:02 [PATCH 00/86] refactor main RAM allocation to use hostmem backend Igor Mammedov
2019-12-31 13:02 ` [PATCH 01/86] numa: remove not needed check Igor Mammedov
2019-12-31 13:02 ` [PATCH 02/86] numa: properly check if numa is supported Igor Mammedov
2019-12-31 13:02 ` [PATCH 03/86] numa: remove deprecated -mem-path fallback to anonymous RAM Igor Mammedov
2019-12-31 13:02 ` [PATCH 04/86] machine: introduce ram-memdev property Igor Mammedov
2019-12-31 13:02 ` [PATCH 05/86] machine: alias -mem-path and -mem-prealloc into memory-foo backend Igor Mammedov
2019-12-31 13:02 ` [PATCH 06/86] machine: introduce convenience MachineState::ram Igor Mammedov
2019-12-31 13:02 ` [PATCH 07/86] initialize MachineState::ram in NUMA case Igor Mammedov
2019-12-31 13:02 ` [PATCH 08/86] alpha:dp264: use memdev for RAM Igor Mammedov
2019-12-31 16:11   ` Philippe Mathieu-Daudé
2020-01-06  0:37   ` Richard Henderson
2019-12-31 13:02 ` [PATCH 09/86] arm:aspeed: convert valid RAM sizes to data Igor Mammedov
2019-12-31 13:02 ` [PATCH 10/86] arm:aspeed: actually check RAM size Igor Mammedov
2019-12-31 13:02 ` [PATCH 11/86] hw:aspeed: drop warning and bogus ram_size fixup Igor Mammedov
2019-12-31 13:02 ` [PATCH 12/86] arm:aspeed: use memdev for RAM Igor Mammedov
2019-12-31 13:02 ` [PATCH 13/86] arm:collie: " Igor Mammedov
2019-12-31 13:02 ` [PATCH 14/86] arm:cubieboard: " Igor Mammedov
2019-12-31 13:02 ` [PATCH 15/86] arm:digic_boards: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 16/86] arm:highbank: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 17/86] arm:imx25_pdk: drop RAM size fixup Igor Mammedov
2019-12-31 13:03 ` [PATCH 18/86] arm:imx25_pdk: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 19/86] arm:integratorcp: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 20/86] arm:kzm: drop RAM size fixup Igor Mammedov
2019-12-31 13:03 ` [PATCH 21/86] arm:kzm: use memdev for RAM Igor Mammedov
2019-12-31 16:10   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 22/86] arm:mcimx6ul-evk: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 23/86] arm:mcimx7d-sabre: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 24/86] arm:mps2-tz: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 25/86] arm:mps2: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 26/86] arm:musicpal: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 27/86] arm:nseries: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 28/86] arm:omap_sx1: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 29/86] arm:palm: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 30/86] arm:raspi: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 31/86] arm:sabrelite: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 32/86] arm:sbsa-ref: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 33/86] arm:versatilepb: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 34/86] arm:vexpress: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 35/86] arm:virt: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 36/86] arm:xilinx_zynq: drop RAM size fixup Igor Mammedov
2019-12-31 13:03 ` [PATCH 37/86] arm:xilinx_zynq: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 38/86] arm:xlnx-versal-virt: " Igor Mammedov
2019-12-31 16:05   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 39/86] arm:xlnx-zcu102: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 40/86] s390x:s390-virtio-ccw: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 41/86] null-machine: " Igor Mammedov
2019-12-31 15:32   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 42/86] cris:axis_dev88: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 43/86] hppa: drop RAM size fixup Igor Mammedov
2019-12-31 15:44   ` Philippe Mathieu-Daudé
2020-01-02 11:31     ` Helge Deller
2020-01-02 12:06       ` Philippe Mathieu-Daudé
2020-01-02 13:02         ` Helge Deller
2020-01-02 14:47           ` Igor Mammedov
2020-01-02 14:12         ` Igor Mammedov
2020-01-02 14:17           ` Philippe Mathieu-Daudé
2020-01-02 15:08             ` Igor Mammedov
2020-01-02 15:49               ` Philippe Mathieu-Daudé
2020-01-02 16:50                 ` Igor Mammedov
2020-01-02 17:14                   ` Philippe Mathieu-Daudé
2020-01-02 17:32                     ` Igor Mammedov
2020-01-02 20:09                 ` Helge Deller
2020-01-02 14:41       ` Igor Mammedov
2020-01-02 14:45         ` Philippe Mathieu-Daudé
2020-01-02 15:35           ` Igor Mammedov
2020-01-02 15:40             ` Philippe Mathieu-Daudé
2020-01-02 17:08   ` [PATCH] hppa: allow max ram size upto 4Gb Igor Mammedov
2020-01-02 17:15     ` Philippe Mathieu-Daudé
2020-01-02 17:36       ` Igor Mammedov
2020-01-02 17:46       ` [PATCH v2] " Igor Mammedov
2020-01-02 20:22         ` Helge Deller
2020-01-03  9:54           ` Igor Mammedov
2020-01-04 15:00             ` Philippe Mathieu-Daudé
2020-01-06 10:48               ` Igor Mammedov
2020-01-06 11:05                 ` Philippe Mathieu-Daudé
2020-01-06 11:28                 ` Helge Deller
2020-01-06 16:24                   ` Igor Mammedov
2020-01-06 17:03                     ` Helge Deller
2020-01-07 11:21                       ` Igor Mammedov
2020-01-07 11:53                         ` Helge Deller
2020-01-07 15:17                           ` Igor Mammedov [this message]
2020-01-07 15:34   ` [PATCH v3 43/86] " Igor Mammedov
2019-12-31 13:03 ` [PATCH 44/86] hppa: use memdev for RAM Igor Mammedov
2019-12-31 15:45   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 45/86] x86:microvm: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 46/86] x86:pc: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 47/86] lm32:lm32_boards: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 48/86] lm32:milkymist: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 49/86] m68k:an5206: " Igor Mammedov
2020-01-07 16:11   ` Thomas Huth
2019-12-31 13:03 ` [PATCH 50/86] m68k:mcf5208: " Igor Mammedov
2020-01-07 16:11   ` Thomas Huth
2019-12-31 13:03 ` [PATCH 51/86] m68k:next-cube: " Igor Mammedov
2020-01-07 16:12   ` Thomas Huth
2019-12-31 13:03 ` [PATCH 52/86] mips:boston-cube: " Igor Mammedov
2019-12-31 16:08   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 53/86] mips:mips_fulong2e: drop RAM size fixup Igor Mammedov
2019-12-31 13:03 ` [PATCH 54/86] mips:mips_fulong2e: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 55/86] mips:mips_jazz: " Igor Mammedov
2019-12-31 16:06   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 56/86] mips:mips_malta: " Igor Mammedov
2019-12-31 16:07   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 57/86] mips:mips_mipssim: " Igor Mammedov
2019-12-31 16:07   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 58/86] mips:mips_r4k: " Igor Mammedov
2019-12-31 16:08   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 59/86] ppc:e500: drop RAM size fixup Igor Mammedov
2019-12-31 13:03 ` [PATCH 60/86] ppc:e500: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 61/86] ppc:mac_newworld: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 62/86] ppc:mac_oldworld: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 63/86] ppc:pnv: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 64/86] ppc:ppc405_boards: add RAM size checks Igor Mammedov
2019-12-31 13:03 ` [PATCH 65/86] ppc:ppc405_boards: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 66/86] ppc:ppc440_bamboo/sam460ex: drop RAM size fixup Igor Mammedov
2020-01-01 11:54   ` BALATON Zoltan
2020-01-01 15:39     ` Philippe Mathieu-Daudé
2020-01-01 18:45       ` BALATON Zoltan
2020-01-02 11:47     ` Igor Mammedov
2020-01-02 15:52       ` BALATON Zoltan
2020-01-02 17:19         ` Igor Mammedov
2020-01-10 17:14         ` Igor Mammedov
2019-12-31 13:03 ` [PATCH 67/86] ppc:ppc440_bamboo/sam460ex: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 68/86] ppc:prep: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 69/86] ppc:spapr: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 70/86] ppc:virtex_ml507: remove unused arguments Igor Mammedov
2019-12-31 13:03 ` [PATCH 71/86] ppc:virtex_ml507: use memdev for RAM Igor Mammedov
2019-12-31 13:03 ` [PATCH 72/86] sparc:leon3: " Igor Mammedov
2019-12-31 16:02   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 73/86] sparc:sun4m: " Igor Mammedov
2019-12-31 13:03 ` [PATCH 74/86] sparc:niagara: " Igor Mammedov
2019-12-31 16:02   ` Philippe Mathieu-Daudé
2019-12-31 13:03 ` [PATCH 75/86] remove no longer used memory_region_allocate_system_memory() Igor Mammedov
2019-12-31 13:04 ` [PATCH 76/86] post conversion default_ram_id cleanup Igor Mammedov
2019-12-31 16:04   ` Philippe Mathieu-Daudé
2019-12-31 13:04 ` [PATCH 77/86] exec: cleanup qemu_minrampagesize()/qemu_maxrampagesize() Igor Mammedov
2019-12-31 13:04 ` [PATCH 78/86] exec: drop bogus mem_path from qemu_ram_alloc_from_fd() Igor Mammedov
2019-12-31 13:04 ` [PATCH 79/86] make mem_path local variable Igor Mammedov
2019-12-31 13:04 ` [PATCH 80/86] hostmem: introduce "prealloc-threads" property Igor Mammedov
2019-12-31 13:04 ` [PATCH 81/86] hostmem: fix strict bind policy Igor Mammedov
2019-12-31 13:04 ` [PATCH 82/86] numa: forbid '-numa node, mem' for 5.0 and newer machine types Igor Mammedov
2019-12-31 13:04 ` [PATCH 83/86] tests:numa-test: make top level args dynamic and g_autofree(cli) cleanups Igor Mammedov
2019-12-31 13:04 ` [PATCH 84/86] tests:numa-test: use explicit memdev to specify node RAM Igor Mammedov
2019-12-31 13:04 ` [PATCH 85/86] numa: make exit() usage consistent Igor Mammedov
2019-12-31 13:04 ` [PATCH 86/86] numa: remove deprecated implicit RAM distribution between nodes Igor Mammedov
2019-12-31 15:58 ` [PATCH 00/86] refactor main RAM allocation to use hostmem backend Philippe Mathieu-Daudé
2019-12-31 16:22   ` Igor Mammedov
2020-01-03 13:06   ` Igor Mammedov
2020-01-03 13:15     ` Philippe Mathieu-Daudé

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