From: Anthony PERARD <anthony.perard@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"Ian Jackson" <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH] libxl/x86: check return value of SHADOW_OP_SET_ALLOCATION domctl
Date: Thu, 1 Jul 2021 10:36:58 +0100 [thread overview]
Message-ID: <YN2Mujj8jKGv7tik@perard> (raw)
In-Reply-To: <5d2bb2cf-8c0c-7300-c895-75bef0e50817@suse.com>
On Mon, Jun 28, 2021 at 01:47:03PM +0200, Jan Beulich wrote:
> The hypervisor may not have enough memory to satisfy the request.
>
> Requested-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> ---
> Especially if the request was mostly fulfilled, guests may have done
> fine despite the failure, so there is a risk of perceived regressions
> here. But not checking the error at all was certainly wrong.
>
> --- a/tools/libs/light/libxl_x86.c
> +++ b/tools/libs/light/libxl_x86.c
> @@ -531,8 +531,18 @@ int libxl__arch_domain_create(libxl__gc
> if (d_config->b_info.type != LIBXL_DOMAIN_TYPE_PV) {
> unsigned long shadow = DIV_ROUNDUP(d_config->b_info.shadow_memkb,
> 1024);
> - xc_shadow_control(ctx->xch, domid, XEN_DOMCTL_SHADOW_OP_SET_ALLOCATION,
> - NULL, 0, &shadow, 0, NULL);
> + int rc = xc_shadow_control(ctx->xch, domid,
Could you use 'r' instead of 'rc' ? The later is reserved for libxl
error codes while the former is for system and libxc calls.
> + XEN_DOMCTL_SHADOW_OP_SET_ALLOCATION,
> + NULL, 0, &shadow, 0, NULL);
> +
> + if (rc) {
xc_shadow_control seems to return "domctl.u.shadow_op.pages" in some
cases, are all non-zero return value errors?
> + LOGED(ERROR, domid,
> + "Failed to set %s allocation: %d (errno:%d)\n",
LOGED already prints prints the meaning of the "errno" value, so we
don't need to log it.
> + libxl_defbool_val(d_config->c_info.hap) ? "HAP" : "shadow",
> + rc, errno);
Is the return value of xc_shadow_control() actually useful when errno is
already logged?
Thanks,
--
Anthony PERARD
next prev parent reply other threads:[~2021-07-01 9:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 11:47 [PATCH] libxl/x86: check return value of SHADOW_OP_SET_ALLOCATION domctl Jan Beulich
2021-06-28 15:59 ` Andrew Cooper
2021-07-01 9:36 ` Anthony PERARD [this message]
2021-07-02 12:29 ` Jan Beulich
2021-07-02 14:46 ` Anthony PERARD
2021-07-02 15:12 ` Jan Beulich
2021-07-02 15:14 ` Jan Beulich
2021-07-02 15:51 ` Anthony PERARD
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