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Re: [Qemu-arm] [PATCH v10 10/10] hw/arm/virt: Bump the 255GB initial RAM
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-arm] [PATCH v10 10/10] hw/arm/virt: Bump the 255GB initial RAM limit |
Date: |
Thu, 28 Feb 2019 17:29:38 +0100 |
On Thu, 28 Feb 2019 16:03:24 +0100
Eric Auger <address@hidden> wrote:
> Now we have the extended memory map (high IO regions beyond the
> scalable RAM) and dynamic IPA range support at KVM/ARM level
> we can bump the legacy 255GB initial RAM limit. The actual maximum
> RAM size now depends on the physical CPU and host kernel, in
> accelerated mode. In TCG mode, it depends on the VCPU
> AA64MMFR0.PARANGE.
>
> Signed-off-by: Eric Auger <address@hidden>
>
> ---
> v7 -> v8:
> - TCG PAMAX check moved in a separate patch
>
> v6 -> v7
> - handle TCG case
> - set_memmap modifications moved to previous patches
> ---
> hw/arm/virt.c | 21 +--------------------
> 1 file changed, 1 insertion(+), 20 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index a3da75a5ae..a45f0fcf79 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -95,21 +95,8 @@
>
> #define PLATFORM_BUS_NUM_IRQS 64
>
> -/* RAM limit in GB. Since VIRT_MEM starts at the 1GB mark, this means
> - * RAM can go up to the 256GB mark, leaving 256GB of the physical
> - * address space unallocated and free for future use between 256G and 512G.
> - * If we need to provide more RAM to VMs in the future then we need to:
> - * * allocate a second bank of RAM starting at 2TB and working up
> - * * fix the DT and ACPI table generation code in QEMU to correctly
> - * report two split lumps of RAM to the guest
> - * * fix KVM in the host kernel to allow guests with >40 bit address spaces
> - * (We don't want to fill all the way up to 512GB with RAM because
> - * we might want it for non-RAM purposes later. Conversely it seems
> - * reasonable to assume that anybody configuring a VM with a quarter
> - * of a terabyte of RAM will be doing it on a host with more than a
> - * terabyte of physical address space.)
> - */
> #define RAMBASE GiB
> +/* Legacy RAM limit in GB (< version 4.0) */
> #define LEGACY_RAMLIMIT_GB 255
> #define LEGACY_RAMLIMIT_BYTES (LEGACY_RAMLIMIT_GB * GiB)
do we need to keep these couple around?
it's used only in
[VIRT_MEM] = { RAMBASE, LEGACY_RAMLIMIT_BYTES },
and doesn't have any effect whatsoever.
I'd set initial VIRT_MEM.size to 0 and drop LEGACY_RAMLIMIT_*
maybe add comment above entry that size is defined by ram_size
>
> @@ -1515,12 +1502,6 @@ static void machvirt_init(MachineState *machine)
>
> vms->smp_cpus = smp_cpus;
>
> - if (machine->ram_size > vms->memmap[VIRT_MEM].size) {
> - error_report("mach-virt: cannot model more than %dGB RAM",
> - LEGACY_RAMLIMIT_GB);
> - exit(1);
> - }
> -
> if (vms->virt && kvm_enabled()) {
> error_report("mach-virt: KVM does not support providing "
> "Virtualization extensions to the guest CPU");
- [Qemu-arm] [PATCH v10 03/10] hw/arm/virt: Split the memory map description, (continued)
- [Qemu-arm] [PATCH v10 03/10] hw/arm/virt: Split the memory map description, Eric Auger, 2019/02/28
- [Qemu-arm] [PATCH v10 06/10] vl: Set machine ram_size, maxram_size and ram_slots earlier, Eric Auger, 2019/02/28
- [Qemu-arm] [PATCH v10 05/10] kvm: add kvm_arm_get_max_vm_ipa_size, Eric Auger, 2019/02/28
- [Qemu-arm] [PATCH v10 07/10] hw/arm/virt: Dynamic memory map depending on RAM requirements, Eric Auger, 2019/02/28
- [Qemu-arm] [PATCH v10 08/10] hw/arm/virt: Implement kvm_type function for 4.0 machine, Eric Auger, 2019/02/28
- [Qemu-arm] [PATCH v10 10/10] hw/arm/virt: Bump the 255GB initial RAM limit, Eric Auger, 2019/02/28
- Re: [Qemu-arm] [PATCH v10 10/10] hw/arm/virt: Bump the 255GB initial RAM limit,
Igor Mammedov <=
- [Qemu-arm] [PATCH v10 09/10] hw/arm/virt: Check the VCPU PA range in TCG mode, Eric Auger, 2019/02/28