On Wed, 25 May 2022 12:23:41 +0100
Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote:
Hi,
> From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>
> Allow the user to use the standard B (bytes), K (kilobytes), M (megabytes),
> G (gigabytes), T (terabytes) and P (petabytes) suffixes for memory size.
> When none are specified, the default is megabytes.
>
> Also raise an error if the guest specifies 0 as the memory size, instead
> of treating it as uninitialized, as kvmtool has done so far.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
> ---
> builtin-run.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 60 insertions(+), 5 deletions(-)
>
> diff --git a/builtin-run.c b/builtin-run.c
> index 2ef159cdb2a3..a49698d5b2fe 100644
> --- a/builtin-run.c
> +++ b/builtin-run.c
> @@ -49,9 +49,11 @@
> #include <ctype.h>
> #include <stdio.h>
>
> -#define MB_SHIFT (20)
> #define KB_SHIFT (10)
> +#define MB_SHIFT (20)
> #define GB_SHIFT (30)
> +#define TB_SHIFT (40)
> +#define PB_SHIFT (50)
Can we lose the parentheses?
>
> __thread struct kvm_cpu *current_kvm_cpu;
>
> @@ -87,6 +89,60 @@ void kvm_run_set_wrapper_sandbox(void)
> kvm_run_wrapper = KVM_RUN_SANDBOX;
> }
>
> +static int parse_mem_unit(char **next)
> +{
> + int shift = -1;
> +
> + switch (**next) {
> + case 'B': case 'b': shift = 0; break;
> + case 'K': case 'k': shift = KB_SHIFT; break;
> + case 'M': case 'm': shift = MB_SHIFT; break;
> + case 'G': case 'g': shift = GB_SHIFT; break;
> + case 'T': case 't': shift = TB_SHIFT; break;
> + case 'P': case 'p': shift = PB_SHIFT; break;
> + }
> +
> + if (shift == -1) {
> + /* The default is megabytes. */
> + shift = MB_SHIFT;
Doesn't that look better inside the switch/case?
default: return MB_SHIFT;
> + } else {
> + (*next)++;
> + }
> +
> + return shift;
> +}
> +
> +static u64 parse_mem_option(const char *nptr, char **next)
> +{
> + u64 shift;
> + u64 val;
> +
> + val = strtoull(nptr, next, 10);
> + if (errno == ERANGE)
> + die("Memory too large: %s", nptr);
strtoull does not clear errno if it succeeds, so it retains the
previous error value. So we would need to set errno to 0 just before
calling strtoull.
> + shift = parse_mem_unit(next);
> +
> + if ((val << shift) < val)
> + die("Memory too large: %s", nptr);
> +
> + return val << shift;
> +}
> +
> +static int mem_parser(const struct option *opt, const char *arg, int unset)
> +{
> + struct kvm *kvm = opt->ptr;
> + char *next;
> +
> + kvm->cfg.ram_size = parse_mem_option(arg, &next);
> + if (kvm->cfg.ram_size == 0)
> + die("Invalid RAM size: %s", arg);
Does 0 hold any significant value (anymore)? I think we die() if we
encounter invalid values in parse_mem_option()?
Cheers,
Andre
> +
> + if (*next != '\0')
> + die("Invalid memory specifier: %s", arg);
> +
> + return 0;
> +}
> +
> #ifndef OPT_ARCH_RUN
> #define OPT_ARCH_RUN(...)
> #endif
> @@ -97,8 +153,9 @@ void kvm_run_set_wrapper_sandbox(void)
> OPT_STRING('\0', "name", &(cfg)->guest_name, "guest name", \
> "A name for the guest"), \
> OPT_INTEGER('c', "cpus", &(cfg)->nrcpus, "Number of CPUs"), \
> - OPT_U64('m', "mem", &(cfg)->ram_size, "Virtual machine memory" \
> - " size in MB."), \
> + OPT_CALLBACK('m', "mem", NULL, "size[BKMGTP]", \
> + "Virtual machine memory size, by default measured" \
> + " in megabytes (M)", mem_parser, kvm), \
> OPT_CALLBACK('d', "disk", kvm, "image or rootfs_dir", "Disk " \
> " image or rootfs directory", img_name_parser, \
> kvm), \
> @@ -522,8 +579,6 @@ static void kvm_run_validate_cfg(struct kvm *kvm)
> pr_warning("Ignoring initrd file when loading a firmware image");
>
> if (kvm->cfg.ram_size) {
> - /* User specifies RAM size in megabytes. */
> - kvm->cfg.ram_size <<= MB_SHIFT;
> available_ram = host_ram_size();
> if (available_ram && kvm->cfg.ram_size > available_ram) {
> pr_warning("Guest memory size %lluMB exceeds host physical RAM size %lluMB",
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