Mailing List Archive: [PATCH v4 2/5] tools/init-xenstore-domain: Replace variable MB() usage

The local MB() & GB() macros will be replaced with a common
implementation, but those only work with constant values. Introduce a
static inline mb_to_bytes() in place of the MB() macro to convert the
variable values.

Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
---
v4:
New
---
tools/helpers/init-xenstore-domain.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/helpers/init-xenstore-domain.c b/tools/helpers/init-xenstore-domain.c
index 1683438c5c..5405842dfe 100644
--- a/tools/helpers/init-xenstore-domain.c
+++ b/tools/helpers/init-xenstore-domain.c
@@ -20,7 +20,6 @@
#include "init-dom-json.h"

#define LAPIC_BASE_ADDRESS 0xfee00000UL
-#define MB(x) ((uint64_t)x << 20)
#define GB(x) ((uint64_t)x << 30)

static uint32_t domid = ~0;
@@ -36,6 +35,11 @@ static xc_evtchn_port_or_error_t console_evtchn;
static xentoollog_level minmsglevel = XTL_PROGRESS;
static void *logger;

+static inline uint64_t mb_to_bytes(int mem)
+{
+ return (uint64_t)mem << 20;
+}
+
static struct option options[] = {
{ "kernel", 1, NULL, 'k' },
{ "memory", 1, NULL, 'm' },
@@ -76,8 +80,8 @@ static int build(xc_interface *xch)
int rv, xs_fd;
struct xc_dom_image *dom = NULL;
int limit_kb = (maxmem ? : memory) * 1024 + X86_HVM_NR_SPECIAL_PAGES * 4;
- uint64_t mem_size = MB(memory);
- uint64_t max_size = MB(maxmem ? : memory);
+ uint64_t mem_size = mb_to_bytes(memory);
+ uint64_t max_size = mb_to_bytes(maxmem ? : memory);
struct e820entry e820[3];
struct xen_domctl_createdomain config = {
.ssidref = SECINITSID_DOMU,
--
2.44.0

On Mon, Mar 25, 2024 at 04:45:12PM -0400, Jason Andryuk wrote:
> The local MB() & GB() macros will be replaced with a common
> implementation, but those only work with constant values. Introduce a
> static inline mb_to_bytes() in place of the MB() macro to convert the
> variable values.
>
> Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
> ---
> v4:
> New
> ---
> tools/helpers/init-xenstore-domain.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/tools/helpers/init-xenstore-domain.c b/tools/helpers/init-xenstore-domain.c
> index 1683438c5c..5405842dfe 100644
> --- a/tools/helpers/init-xenstore-domain.c
> +++ b/tools/helpers/init-xenstore-domain.c
> @@ -20,7 +20,6 @@
> #include "init-dom-json.h"
>
> #define LAPIC_BASE_ADDRESS 0xfee00000UL
> -#define MB(x) ((uint64_t)x << 20)
> #define GB(x) ((uint64_t)x << 30)
>
> static uint32_t domid = ~0;
> @@ -36,6 +35,11 @@ static xc_evtchn_port_or_error_t console_evtchn;
> static xentoollog_level minmsglevel = XTL_PROGRESS;
> static void *logger;
>
> +static inline uint64_t mb_to_bytes(int mem)
> +{
> + return (uint64_t)mem << 20;
> +}
> +
> static struct option options[] = {
> { "kernel", 1, NULL, 'k' },
> { "memory", 1, NULL, 'm' },
> @@ -76,8 +80,8 @@ static int build(xc_interface *xch)
> int rv, xs_fd;
> struct xc_dom_image *dom = NULL;
> int limit_kb = (maxmem ? : memory) * 1024 + X86_HVM_NR_SPECIAL_PAGES * 4;
> - uint64_t mem_size = MB(memory);
> - uint64_t max_size = MB(maxmem ? : memory);
> + uint64_t mem_size = mb_to_bytes(memory);
> + uint64_t max_size = mb_to_bytes(maxmem ? : memory);

Looks like this change actually fix a bug. When `maxmem` is set, we
would have "max_size = maxmem", otherwise, it would be
"max_size = memory << 20"

The macro should have been written as
#define MB(x) ((uint64_t)(x) << 20)

This patch could be backported to 4.17 and later, with:
Fixes: 134d53f57707 ("tools/init-xenstore-domain: fix memory map for PVH stubdom")

Anyway, this patch on it's own looks fine:
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>

Thanks,

--
Anthony PERARD