From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cdPKE-0004Ty-Cr for kexec@lists.infradead.org; Mon, 13 Feb 2017 22:42:28 +0000 Date: Mon, 13 Feb 2017 23:41:56 +0100 From: Daniel Kiper Subject: Re: [PATCH v3 11/11] kexec: Add option to get crash kernel region size Message-ID: <20170213224156.GI9543@olila.local.net-space.pl> References: <1486764462-14176-1-git-send-email-eric.devolder@oracle.com> <1486764462-14176-12-git-send-email-eric.devolder@oracle.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1486764462-14176-12-git-send-email-eric.devolder@oracle.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Eric DeVolder Cc: panand@redhat.com, konrad.wilk@oracle.com, andrew.cooper3@citrix.com, kexec@lists.infradead.org, horms@verge.net.au, dyoung@redhat.com On Fri, Feb 10, 2017 at 04:07:42PM -0600, Eric DeVolder wrote: > From: Daniel Kiper > > From: Daniel Kiper Hmmm... One is sufficient... > Crash kernel region size is available via sysfs on Linux running on > bare metal. However, this does not work when Linux runs as Xen dom0. > In this case Xen crash kernel region size should be established using > __HYPERVISOR_kexec_op hypercall (Linux kernel kexec functionality does > not make a lot of sense in Xen dom0). Sadly hypercalls are not easily > accessible using shell scripts or something like that. Potentially we > can check "xl dmesg" output for crashkernel option but this is not nice. > So, let's add this functionality, for Linux running on bare metal and > as Xen dom0, to kexec-tools. This way kdump scripts may establish crash > kernel region size in one way regardless of platform. All burden of > platform detection lies on kexec-tools. > > Figure (and unit) displayed by this new kexec-tools functionality is > the same as one taken from /sys/kernel/kexec_crash_size. > > Signed-off-by: Daniel Kiper > Signed-off-by: Eric DeVolder > --- > kexec/kexec.8 | 3 +++ > kexec/kexec.c | 20 ++++++++++++++++++++ > kexec/kexec.h | 4 +++- > 3 files changed, 26 insertions(+), 1 deletion(-) > > diff --git a/kexec/kexec.8 b/kexec/kexec.8 > index f4b39a6..e0131b4 100644 > --- a/kexec/kexec.8 > +++ b/kexec/kexec.8 > @@ -179,6 +179,9 @@ Load a helper image to jump back to original kernel. > .TP > .BI \-\-reuseinitrd > Reuse initrd from first boot. > +.TP > +.BI \-\-print-ckr-size > +Print crash kernel region size, if available. > > > .SH SUPPORTED KERNEL FILE TYPES AND OPTIONS > diff --git a/kexec/kexec.c b/kexec/kexec.c > index a2ba79d..0be1be4 100644 > --- a/kexec/kexec.c > +++ b/kexec/kexec.c > @@ -995,6 +995,7 @@ void usage(void) > " --mem-max= Specify the highest memory address to\n" > " load code into.\n" > " --reuseinitrd Reuse initrd from first boot.\n" > + " --print-ckr-size Print crash kernel region size.\n" > " --load-preserve-context Load the new kernel and preserve\n" > " context of current kernel during kexec.\n" > " --load-jump-back-helper Load a helper image to jump back\n" > @@ -1218,6 +1219,22 @@ static int do_kexec_file_load(int fileind, int argc, char **argv, > return ret; > } > > +static void print_crashkernel_region_size(void) > +{ > + uint64_t start = 0, end = 0; This initialization is not needed. > + > + if (is_crashkernel_mem_reserved()) { > + int ret = get_crash_kernel_load_range(&start, &end); I do not like mixing code with variable declarations. > + if (ret != 0) { if (ret) > + fprintf(stderr, "get_crash_kernel_load_range failed.\n"); s/get_crash_kernel_load_range/get_crash_kernel_load_range()/ > + return; > + } > + } Please add empty line here. > + if (start != end) if (!ret && start != end) There is no guarantee that in case of error nobody touched start and/or end in get_crash_kernel_load_range() call. > + printf("%lu\n", end - start + 1); > + else > + printf("0\n"); > +} Daniel _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec