On Fri, 19 Mar 2021 16:17:09 +0000,
Yoan Picchi <yoan.picchi@xxxxxxx> wrote:
>
> Add a counter for when a memory slot is unmapped, meaning that all
> memory belonging to a specific VM is made available to be mapped for
> anoother VM.
No. It just means it is unmapped from the guest. The VMM still has the
pages.
> A memory slot is the memory that can be used to hold a
> guest's pages and can be made available by Qemu for instance. For
> now the memory slot are only unmapped when a vm restarts.
>
> Signed-off-by: Yoan Picchi <yoan.picchi@xxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 1 +
> arch/arm64/kvm/guest.c | 1 +
> arch/arm64/kvm/mmu.c | 1 +
> 3 files changed, 3 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index e6967951f..76c81aa79 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -548,6 +548,7 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
> struct kvm_vm_stat {
> ulong remote_tlb_flush;
> ulong flush_all_cache_lines;
> + ulong memory_slot_unmaped;
> ulong cached_page_invalidated;
> };
>
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index d948c3bd2..cd227136e 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -42,6 +42,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
> VCPU_STAT("huge_page_mapped", huge_page_mapped),
> VM_STAT("remote_tlb_flush", remote_tlb_flush),
> VM_STAT("flush_all_cache_lines", flush_all_cache_lines),
> + VM_STAT("memory_slot_unmaped", memory_slot_unmaped),
> VM_STAT("cached_page_invalidated", cached_page_invalidated),
> VCPU_STAT("exits", exits),
> VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 985b048df..1e8aeafc2 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -419,6 +419,7 @@ static void stage2_unmap_memslot(struct kvm *kvm,
> phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
> phys_addr_t size = PAGE_SIZE * memslot->npages;
> hva_t reg_end = hva + size;
> + kvm->stat.memory_slot_unmaped++;
Why is that a relevant thing to track? You even increment the counter
before even checking whether this will unmap anything... :-(
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
