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Thu, 08 Oct 2020 15:46:44 +0000 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 9182a750-5deb-43f4-a89b-75c0cbb7b4d5; Thu, 08 Oct 2020 15:46:42 +0000 (UTC) Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0092220739; Thu, 8 Oct 2020 15:46:39 +0000 (UTC) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 9182a750-5deb-43f4-a89b-75c0cbb7b4d5 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602172001; bh=URIrqbBZFVv8zRZdEp54wBusdj0zVHMR07U5vdNs8mo=; h=From:To:Cc:Subject:Date:From; b=TZ9QNy0j3cHF52KEoAsDg3e2O0fg8cBtYwcgVxf6EsTB8WYcC7QGE6i0PceSPVN/z 2b5yTSx3VmP0gAz5PALL10zmdiXh1x059sJ8/zFq0PKFRzsaQAoFrL8eDPMvP3OOdt UTkzTKRamDYaHTkQbpzFiTjKWRLx+FAKtndIePUc= From: Masami Hiramatsu To: Stefano Stabellini , Julien Grall Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , takahiro.akashi@linaro.org Subject: [PATCH v3] arm/arm64: xen: Fix to convert percpu address to gfn correctly Date: Fri, 9 Oct 2020 00:46:37 +0900 Message-Id: <160217199753.214054.18187130778764820148.stgit@devnote2> X-Mailer: git-send-email 2.25.1 User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @kernel.org) Use per_cpu_ptr_to_phys() instead of virt_to_phys() and __pa() for per-cpu address conversion. In xen_starting_cpu(), per-cpu xen_vcpu_info address is converted to gfn by virt_to_gfn() macro. However, since the virt_to_gfn(v) assumes the given virtual address is in linear mapped kernel memory area, it can not convert the per-cpu memory if it is allocated on vmalloc area. This depends on from where the xen_vcpu_info percpu object is allocated. If CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK=3Dy, the first chunk of percpu is on the kernel linear mapped area. If the first chunk is enough large, xen_guest_init() can allocate the xen_vcpu_info on the first chunk. However, if it is not large enough, or other subsystem init functions called earlier than xen_guest_init() runs out the first chunk, the xen_vcpu_info is allocated on the 2nd chunk of percpu, and it can be on vmalloc memory (depends on CONFIG_NEED_PER_CPU_KM=3Dn). Without this fix and, unfortnunately, xen_vcpu_info is allocated on the vmalloc area, the Dom0 kernel will fail to boot with following errors. [ 0.466172] Xen: initializing cpu0 [ 0.469601] ------------[ cut here ]------------ [ 0.474295] WARNING: CPU: 0 PID: 1 at arch/arm64/xen/../../arm/xen/enlig= hten.c:153 xen_starting_cpu+0x160/0x180 [ 0.484435] Modules linked in: [ 0.487565] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc4+ #4 [ 0.493895] Hardware name: Socionext Developer Box (DT) [ 0.499194] pstate: 00000005 (nzcv daif -PAN -UAO BTYPE=3D--) [ 0.504836] pc : xen_starting_cpu+0x160/0x180 [ 0.509263] lr : xen_starting_cpu+0xb0/0x180 [ 0.513599] sp : ffff8000116cbb60 [ 0.516984] x29: ffff8000116cbb60 x28: ffff80000abec000 [ 0.522366] x27: 0000000000000000 x26: 0000000000000000 [ 0.527754] x25: ffff80001156c000 x24: fffffdffbfcdb600 [ 0.533129] x23: 0000000000000000 x22: 0000000000000000 [ 0.538511] x21: ffff8000113a99c8 x20: ffff800010fe4f68 [ 0.543892] x19: ffff8000113a9988 x18: 0000000000000010 [ 0.549274] x17: 0000000094fe0f81 x16: 00000000deadbeef [ 0.554655] x15: ffffffffffffffff x14: 0720072007200720 [ 0.560037] x13: 0720072007200720 x12: 0720072007200720 [ 0.565418] x11: 0720072007200720 x10: 0720072007200720 [ 0.570801] x9 : ffff8000100fbdc0 x8 : ffff800010715208 [ 0.576182] x7 : 0000000000000054 x6 : ffff00001b790f00 [ 0.581564] x5 : ffff800010bbf880 x4 : 0000000000000000 [ 0.586945] x3 : 0000000000000000 x2 : ffff80000abec000 [ 0.592327] x1 : 000000000000002f x0 : 0000800000000000 [ 0.597716] Call trace: [ 0.600232] xen_starting_cpu+0x160/0x180 [ 0.604309] cpuhp_invoke_callback+0xac/0x640 [ 0.608736] cpuhp_issue_call+0xf4/0x150 [ 0.612728] __cpuhp_setup_state_cpuslocked+0x128/0x2c8 [ 0.618030] __cpuhp_setup_state+0x84/0xf8 [ 0.622192] xen_guest_init+0x324/0x364 [ 0.626097] do_one_initcall+0x54/0x250 [ 0.630003] kernel_init_freeable+0x12c/0x2c8 [ 0.634428] kernel_init+0x1c/0x128 [ 0.637988] ret_from_fork+0x10/0x18 [ 0.641635] ---[ end trace d95b5309a33f8b27 ]--- [ 0.646337] ------------[ cut here ]------------ [ 0.651005] kernel BUG at arch/arm64/xen/../../arm/xen/enlighten.c:158! [ 0.657697] Internal error: Oops - BUG: 0 [#1] SMP [ 0.662548] Modules linked in: [ 0.665676] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 5.= 9.0-rc4+ #4 [ 0.673398] Hardware name: Socionext Developer Box (DT) [ 0.678695] pstate: 00000005 (nzcv daif -PAN -UAO BTYPE=3D--) [ 0.684338] pc : xen_starting_cpu+0x178/0x180 [ 0.688765] lr : xen_starting_cpu+0x144/0x180 [ 0.693188] sp : ffff8000116cbb60 [ 0.696573] x29: ffff8000116cbb60 x28: ffff80000abec000 [ 0.701955] x27: 0000000000000000 x26: 0000000000000000 [ 0.707344] x25: ffff80001156c000 x24: fffffdffbfcdb600 [ 0.712718] x23: 0000000000000000 x22: 0000000000000000 [ 0.718107] x21: ffff8000113a99c8 x20: ffff800010fe4f68 [ 0.723481] x19: ffff8000113a9988 x18: 0000000000000010 [ 0.728863] x17: 0000000094fe0f81 x16: 00000000deadbeef [ 0.734245] x15: ffffffffffffffff x14: 0720072007200720 [ 0.739626] x13: 0720072007200720 x12: 0720072007200720 [ 0.745008] x11: 0720072007200720 x10: 0720072007200720 [ 0.750390] x9 : ffff8000100fbdc0 x8 : ffff800010715208 [ 0.755771] x7 : 0000000000000054 x6 : ffff00001b790f00 [ 0.761153] x5 : ffff800010bbf880 x4 : 0000000000000000 [ 0.766534] x3 : 0000000000000000 x2 : 00000000deadbeef [ 0.771916] x1 : 00000000deadbeef x0 : ffffffffffffffea [ 0.777304] Call trace: [ 0.779819] xen_starting_cpu+0x178/0x180 [ 0.783898] cpuhp_invoke_callback+0xac/0x640 [ 0.788325] cpuhp_issue_call+0xf4/0x150 [ 0.792317] __cpuhp_setup_state_cpuslocked+0x128/0x2c8 [ 0.797619] __cpuhp_setup_state+0x84/0xf8 [ 0.801779] xen_guest_init+0x324/0x364 [ 0.805683] do_one_initcall+0x54/0x250 [ 0.809590] kernel_init_freeable+0x12c/0x2c8 [ 0.814016] kernel_init+0x1c/0x128 [ 0.817583] ret_from_fork+0x10/0x18 [ 0.821226] Code: d0006980 f9427c00 cb000300 17ffffea (d4210000) [ 0.827415] ---[ end trace d95b5309a33f8b28 ]--- [ 0.832076] Kernel panic - not syncing: Attempted to kill init! exitcode= =3D0x0000000b [ 0.839815] ---[ end Kernel panic - not syncing: Attempted to kill init!= exitcode=3D0x0000000b ]--- Theoletically, this issue has been introduced by commit 9a9ab3cc00dc ("xen/arm: SMP support") because it uses __pa() on percpu address. Signed-off-by: Masami Hiramatsu Reviewed-by: Stefano Stabellini --- Changes in v3: Update patch description to explain the mechanism of the problem. --- arch/arm/xen/enlighten.c | 2 +- include/xen/arm/page.h | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index e93145d72c26..a6ab3689b2f4 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -150,7 +150,7 @@ static int xen_starting_cpu(unsigned int cpu) pr_info("Xen: initializing cpu%d\n", cpu); vcpup =3D per_cpu_ptr(xen_vcpu_info, cpu); =20 - info.mfn =3D virt_to_gfn(vcpup); + info.mfn =3D percpu_to_gfn(vcpup); info.offset =3D xen_offset_in_page(vcpup); =20 err =3D HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu), diff --git a/include/xen/arm/page.h b/include/xen/arm/page.h index 39df751d0dc4..ac1b65470563 100644 --- a/include/xen/arm/page.h +++ b/include/xen/arm/page.h @@ -83,6 +83,9 @@ static inline unsigned long bfn_to_pfn(unsigned long bfn) }) #define gfn_to_virt(m) (__va(gfn_to_pfn(m) << XEN_PAGE_SHIFT)) =20 +#define percpu_to_gfn(v) \ + (pfn_to_gfn(per_cpu_ptr_to_phys(v) >> XEN_PAGE_SHIFT)) + /* Only used in PV code. But ARM guests are always HVM. */ static inline xmaddr_t arbitrary_virt_to_machine(void *vaddr) {