Re: [Qemu-devel] [PATCH] kvm-all: PAGE_SIZE should be real host page size

[Peter Maydell]

On 10 November 2015 at 00:23, Andrew Jones <address@hidden> wrote:
> Just noticed this while grepping TARGET_PAGE_SIZE for an unrelated
> reason. I didn't use qemu_real_host_page_size as kvm_set_phys_mem()
> does, because we'd need to make sure page_size_init() has run first.
>
> Signed-off-by: Andrew Jones <address@hidden>
> ---
>  kvm-all.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 1bc12737723c3..de9ff5971fb3b 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -45,8 +45,10 @@
>  #include <sys/eventfd.h>
>  #endif
>
> -/* KVM uses PAGE_SIZE in its definition of COALESCED_MMIO_MAX */
> -#define PAGE_SIZE TARGET_PAGE_SIZE
> +/* KVM uses PAGE_SIZE in its definition of KVM_COALESCED_MMIO_MAX. We
> + * need to use the real host PAGE_SIZE, as that's what KVM will use.
> + */
> +#define PAGE_SIZE getpagesize()

Rather than defining PAGE_SIZE here (a confusing macro given
we have several page sizes to deal with), why not just use
getpagesize() in the one and only location where we currently
use this macro?

Also, you're guaranteed that page_size_init() has been run, because
we call that from kvm_init(), and you can't call kvm_vcpu_init()
before kvm_init().

thanks
-- PMM