On Tue, Oct 10, 2017 at 05:21:53PM +0200, Laurent Vivier wrote: > On 10/10/2017 16:44, Greg Kurz wrote: > > On Wed, 11 Oct 2017 00:21:59 +1100 > > David Gibson <da...@gibson.dropbear.id.au> 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 <da...@gibson.dropbear.id.au> > >> --- > >> 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(); > > > > current_ram_size is initialized earlier in this function: > > > > uint64_t current_ram_size = MACHINE(spapr)->ram_size; > > > > which is is initialized to ram_size in vl.c. Why not doing: > > > > current_ram_size += get_plugged_memory_size(); > > > > ? > > I agree, it seems like the original intend of the first patch...
Yes, I think so. However, splitting the calculation like that demonstrably misread someone reading the code (i.e. me), so I'm going to just ditch the initializerin the new spin. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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