On 11/30/2015 01:06 PM, Paul Mackerras wrote:
On Tue, Sep 15, 2015 at 08:49:35PM +1000, Alexey Kardashevskiy wrote:At the moment pages used for TCE tables (in addition to pages addressed by TCEs) are not counted in locked_vm counter so a malicious userspace tool can call ioctl(KVM_CREATE_SPAPR_TCE) as many times as RLIMIT_NOFILE and lock a lot of memory. This adds counting for pages used for TCE tables. This counts the number of pages required for a table plus pages for the kvmppc_spapr_tce_table struct (TCE table descriptor) itself. This does not change the amount of (de)allocated memory. Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx> --- arch/powerpc/kvm/book3s_64_vio.c | 51 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 9526c34..b70787d 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -45,13 +45,56 @@ static long kvmppc_stt_npages(unsigned long window_size) * sizeof(u64), PAGE_SIZE) / PAGE_SIZE; } +static long kvmppc_account_memlimit(long npages, bool inc) +{ + long ret = 0; + const long bytes = sizeof(struct kvmppc_spapr_tce_table) + + (abs(npages) * sizeof(struct page *));Why abs(npages)? Can npages be negative? If so, what does that mean?
Leftover from older versions when there was one shared account_memlimit(long npages). It does not make sense here, I need to remove it.
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