On Mon, 23 Sep 2019 14:35:12 +0100
Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote:
Hi,
> The user can specify the virtual machine memory size, in MB, which is saved
> in cfg->ram_size. kvmtool validates it against the host memory size,
> converted from bytes to MB. ram_size is aftwerwards converted to bytes, and
> this is how it is used throughout the rest of the program.
>
> Let's avoid any confusion about the unit of measurement and always use
> cfg->ram_size in bytes.
... which also means you can get rid of MIN_RAM_SIZE_MB in include/kvm/kvm-config.h.
Otherwise:
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
Cheers,
Andre
> ---
> builtin-run.c | 19 ++++++++++---------
> include/kvm/kvm-config.h | 2 +-
> include/kvm/kvm.h | 2 +-
> 3 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/builtin-run.c b/builtin-run.c
> index cff44047bb1c..4e0c52b3e027 100644
> --- a/builtin-run.c
> +++ b/builtin-run.c
> @@ -262,7 +262,7 @@ static u64 host_ram_size(void)
> return 0;
> }
>
> - return (nr_pages * page_size) >> MB_SHIFT;
> + return nr_pages * page_size;
> }
>
> /*
> @@ -276,11 +276,11 @@ static u64 get_ram_size(int nr_cpus)
> u64 available;
> u64 ram_size;
>
> - ram_size = 64 * (nr_cpus + 3);
> + ram_size = (64 * (nr_cpus + 3)) << MB_SHIFT;
>
> available = host_ram_size() * RAM_SIZE_RATIO;
> if (!available)
> - available = MIN_RAM_SIZE_MB;
> + available = MIN_RAM_SIZE_BYTE;
>
> if (ram_size > available)
> ram_size = available;
> @@ -531,13 +531,14 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
>
> if (!kvm->cfg.ram_size)
> kvm->cfg.ram_size = get_ram_size(kvm->cfg.nrcpus);
> + else
> + /* The user specifies the memory in MB. */
> + kvm->cfg.ram_size <<= MB_SHIFT;
>
> if (kvm->cfg.ram_size > host_ram_size())
> pr_warning("Guest memory size %lluMB exceeds host physical RAM size %lluMB",
> - (unsigned long long)kvm->cfg.ram_size,
> - (unsigned long long)host_ram_size());
> -
> - kvm->cfg.ram_size <<= MB_SHIFT;
> + (unsigned long long)kvm->cfg.ram_size >> MB_SHIFT,
> + (unsigned long long)host_ram_size() >> MB_SHIFT);
>
> if (!kvm->cfg.dev)
> kvm->cfg.dev = DEFAULT_KVM_DEV;
> @@ -647,12 +648,12 @@ static struct kvm *kvm_cmd_run_init(int argc, const char **argv)
> if (kvm->cfg.kernel_filename) {
> printf(" # %s run -k %s -m %Lu -c %d --name %s\n", KVM_BINARY_NAME,
> kvm->cfg.kernel_filename,
> - (unsigned long long)kvm->cfg.ram_size / 1024 / 1024,
> + (unsigned long long)kvm->cfg.ram_size >> MB_SHIFT,
> kvm->cfg.nrcpus, kvm->cfg.guest_name);
> } else if (kvm->cfg.firmware_filename) {
> printf(" # %s run --firmware %s -m %Lu -c %d --name %s\n", KVM_BINARY_NAME,
> kvm->cfg.firmware_filename,
> - (unsigned long long)kvm->cfg.ram_size / 1024 / 1024,
> + (unsigned long long)kvm->cfg.ram_size >> MB_SHIFT,
> kvm->cfg.nrcpus, kvm->cfg.guest_name);
> }
>
> diff --git a/include/kvm/kvm-config.h b/include/kvm/kvm-config.h
> index a052b0bc7582..e0c9ee14e103 100644
> --- a/include/kvm/kvm-config.h
> +++ b/include/kvm/kvm-config.h
> @@ -22,7 +22,7 @@ struct kvm_config {
> struct kvm_config_arch arch;
> struct disk_image_params disk_image[MAX_DISK_IMAGES];
> struct vfio_device_params *vfio_devices;
> - u64 ram_size;
> + u64 ram_size; /* Guest memory size, in bytes */
> u8 image_count;
> u8 num_net_devices;
> u8 num_vfio_devices;
> diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
> index 635ce0f40b1e..a866d5a825c4 100644
> --- a/include/kvm/kvm.h
> +++ b/include/kvm/kvm.h
> @@ -68,7 +68,7 @@ struct kvm {
> struct kvm_cpu **cpus;
>
> u32 mem_slots; /* for KVM_SET_USER_MEMORY_REGION */
> - u64 ram_size;
> + u64 ram_size; /* Guest memory size, in bytes */
> void *ram_start;
> u64 ram_pagesize;
> struct list_head mem_banks;
