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Re: [Qemu-ppc] [PATCH] spapr: Correct RAM size calculation for HPT resiz
Re: [Qemu-ppc] [PATCH] spapr: Correct RAM size calculation for HPT resizing
Tue, 10 Oct 2017 15:59:51 +0200
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0
On 10/10/2017 15:21, David Gibson wrote:
> In order to prevent the guest from forcing the allocation of large amounts
> of qemu memory (or host kernel memory, in the case of KVM HV), we limit
> the size of Hashed Page Table (HPT) it is allowed to allocated, based on
> its RAM size.
> However, the current calculation is not correct: it only adds up the size
> of plugged memory, ignoring the base memory size. This patch corrects it.
> While we're there, use get_plugged_memory_size() instead of directly
> calling pc_existing_dimms_capacity(). The only difference is that it
> will abort on failure, which is right: a failure here indicates something
> wrong within qemu.
> Signed-off-by: David Gibson <address@hidden>
> hw/ppc/spapr_hcall.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 8d72bb7c1c..06af1b15c0 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -494,7 +494,7 @@ static target_ulong h_resize_hpt_prepare(PowerPCCPU *cpu,
> return H_PARAMETER;
> - current_ram_size = pc_existing_dimms_capacity(&error_fatal);
> + current_ram_size = ram_size + get_plugged_memory_size();
> /* We only allow the guest to allocate an HPT one order above what
> * we'd normally give them (to stop a small guest claiming a huge
According to the content of qmp_query_memory_size_summary(), it's the
good way to compute the memory size...
Reviewed-by: Laurent Vivier <address@hidden>