Re: [Crash-utility] [PATCH] Fix pvops Xen detection for arm machine

Hi, Qi Thank you for the fix. > Date: Thu, 16 Dec 2021 15:09:49 +0800 > From: Qi Zheng <zhengqi.arch(a)bytedance.com&gt; > To: k-hagio-ab(a)nec.com, ptesarik(a)suse.com, lijiang(a)redhat.com > Cc: Qi Zheng <zhengqi.arch(a)bytedance.com&gt;, crash-utility(a)redhat.com > Subject: [Crash-utility] [PATCH] Fix pvops Xen detection for arm > machine > Message-ID: <20211216070949.17668-1-zhengqi.arch(a)bytedance.com&gt; > Content-Type: text/plain; charset="US-ASCII" > > Since the xen_start_info on the arm/arm64 platform is static defined: > > ./arm/xen/enlighten.c:40:static struct start_info _xen_start_info; > ./arm/xen/enlighten.c:41:struct start_info *xen_start_info = &_xen_start_info; > ./arm/xen/enlighten.c:42:EXPORT_SYMBOL(xen_start_info); > The above variable is statically defined in the kernel, but the 'xen_vcpu_info' is also a static variable, why does the former not work on arm machines, but the latter works well? Could you please explain more details? [linux]$ grep -nr "xen_vcpu_info" * arch/arm/xen/enlighten.c:51:static struct vcpu_info __percpu *xen_vcpu_info;

Thanks. Lianbo > The is_pvops_xen() in commit 4badc6229c69f5cd9da7eb7bdf400a53ec6db01a > ("Fix pvops Xen detection for kernels >= v4.20") always return TRUE. > Then the following error will be reported because p2m_mid_missing > and xen_p2m_addr are not defined: > > crash: cannot resolve "p2m_top" > > For the arm/arm64 platform, fix it by using xen_vcpu_info instead of > xen_start_info to detect Xen dumps. > > Signed-off-by: Qi Zheng <zhengqi.arch(a)bytedance.com&gt; > --- > kernel.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > diff --git a/kernel.c b/kernel.c > index f4598ea..4b4d789 100644 > --- a/kernel.c > +++ b/kernel.c > @@ -10757,11 +10757,18 @@ is_pvops_xen(void) > STREQ(sym, "paravirt_patch_default"))) > return TRUE; > > - if (symbol_exists("xen_start_info") && > - readmem(symbol_value("xen_start_info"), KVADDR, &addr, > - sizeof(void *), "xen_start_info", RETURN_ON_ERROR) && > - addr != 0) > + if (machine_type("ARM") || machine_type("ARM64")) { > + if (symbol_exists("xen_vcpu_info") && > + readmem(symbol_value("xen_vcpu_info"), KVADDR, &addr, > + sizeof(void *), "xen_vcpu_info", RETURN_ON_ERROR) && > + addr != 0) > + return TRUE; > + } else if (symbol_exists("xen_start_info") && > + readmem(symbol_value("xen_start_info"), KVADDR, &addr, > + sizeof(void *), "xen_start_info", RETURN_ON_ERROR) && > + addr != 0) { > return TRUE; > + } > > return FALSE; > } > -- > 2.11.0