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Tue, 19 Apr 2022 10:18:53 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 26m7K42MXmKFLAAAMHmgww (envelope-from ); Tue, 19 Apr 2022 10:18:53 +0000 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: 1d9d986b-bfca-11ec-8fbe-03012f2f19d4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1650363534; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=v0gLa5Y6O/P0/0TgCgwdis7Q/sd27l3CARbbhyx3ybA=; b=rxbKx9DmOjNjtcqeYKjgoGD6jNWse7Ro5GquN5m+ylvHS0BTI7vRvJQk1lCRB0HnxTdeDr qn1ZS+kRrKJihML5GWKtqB44m+UqjyTn/LuhDVaWAQLJuCV8BWaAK2+M0f3EHZFw6qPbqz I/Ymxsk3ceKee8G4fky4hxR7fdo2Kw8= From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Elena Ufimtseva , Jan Beulich , Andrew Cooper , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Wei Liu , George Dunlap , Julien Grall , Stefano Stabellini , Cheyenne Wills Subject: [PATCH v2] xen: fix XEN_DOMCTL_gdbsx_guestmemio crash Date: Tue, 19 Apr 2022 12:18:50 +0200 Message-Id: <20220419101850.3045-1-jgross@suse.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) X-ZM-MESSAGEID: 1650363562807100001 Content-Type: text/plain; charset="utf-8" A hypervisor built without CONFIG_GDBSX will crash in case the XEN_DOMCTL_gdbsx_guestmemio domctl is being called, as the call will end up in iommu_do_domctl() with d =3D=3D NULL: (XEN) CPU: 6 (XEN) RIP: e008:[] iommu_do_domctl+0x4/0x30 (XEN) RFLAGS: 0000000000010202 CONTEXT: hypervisor (d0v0) (XEN) rax: 00000000000003e8 rbx: ffff830856277ef8 rcx: ffff830856277fff ... (XEN) Xen call trace: (XEN) [] R iommu_do_domctl+0x4/0x30 (XEN) [] S arch_do_domctl+0x7f/0x2330 (XEN) [] S do_domctl+0xe56/0x1930 (XEN) [] S do_domctl+0/0x1930 (XEN) [] S pv_hypercall+0x99/0x110 (XEN) [] S arch/x86/pv/domain.c#_toggle_guest_pt+0x11/= 0x90 (XEN) [] S lstar_enter+0x128/0x130 (XEN) (XEN) Pagetable walk from 0000000000000144: (XEN) L4[0x000] =3D 0000000000000000 ffffffffffffffff (XEN) (XEN) **************************************** (XEN) Panic on CPU 6: (XEN) FATAL PAGE FAULT (XEN) [error_code=3D0000] (XEN) Faulting linear address: 0000000000000144 Fix this issue by modifying the interface of gdbsx_guest_mem_io() to take the already known domain pointer instead of the domid. Reported-by: Cheyenne Wills Fixes: e726a82ca0dc ("xen: make gdbsx support configurable") Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- V2: - use gdbsx_guest_mem_io() interface modification (Jan Beulich) --- xen/arch/x86/debug.c | 10 ++-------- xen/arch/x86/domctl.c | 6 +++--- xen/arch/x86/include/asm/debugger.h | 2 +- xen/common/domctl.c | 1 - 4 files changed, 6 insertions(+), 13 deletions(-) diff --git a/xen/arch/x86/debug.c b/xen/arch/x86/debug.c index d90dc93056..c0dd6eaf15 100644 --- a/xen/arch/x86/debug.c +++ b/xen/arch/x86/debug.c @@ -159,17 +159,11 @@ static unsigned int dbg_rw_guest_mem(struct domain *d= p, unsigned long addr, * Returns: number of bytes remaining to be copied. */ unsigned int dbg_rw_mem(unsigned long gva, XEN_GUEST_HANDLE_PARAM(void) bu= f, - unsigned int len, domid_t domid, bool toaddr, + unsigned int len, struct domain *d, bool toaddr, uint64_t pgd3) { - struct domain *d =3D rcu_lock_domain_by_id(domid); - - if ( d ) - { - if ( !d->is_dying ) + if ( d && !d->is_dying ) len =3D dbg_rw_guest_mem(d, gva, buf, len, toaddr, pgd3); - rcu_unlock_domain(d); - } =20 return len; } diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c index e49f9e91b9..a6aae500a3 100644 --- a/xen/arch/x86/domctl.c +++ b/xen/arch/x86/domctl.c @@ -38,10 +38,10 @@ #include =20 #ifdef CONFIG_GDBSX -static int gdbsx_guest_mem_io(domid_t domid, struct xen_domctl_gdbsx_memio= *iop) +static int gdbsx_guest_mem_io(struct domain *d, struct xen_domctl_gdbsx_me= mio *iop) { iop->remain =3D dbg_rw_mem(iop->gva, guest_handle_from_ptr(iop->uva, v= oid), - iop->len, domid, iop->gwr, iop->pgd3val); + iop->len, d, iop->gwr, iop->pgd3val); =20 return iop->remain ? -EFAULT : 0; } @@ -828,7 +828,7 @@ long arch_do_domctl( #ifdef CONFIG_GDBSX case XEN_DOMCTL_gdbsx_guestmemio: domctl->u.gdbsx_guest_memio.remain =3D domctl->u.gdbsx_guest_memio= .len; - ret =3D gdbsx_guest_mem_io(domctl->domain, &domctl->u.gdbsx_guest_= memio); + ret =3D gdbsx_guest_mem_io(d, &domctl->u.gdbsx_guest_memio); if ( !ret ) copyback =3D true; break; diff --git a/xen/arch/x86/include/asm/debugger.h b/xen/arch/x86/include/asm= /debugger.h index 99803bfd0c..221bcde137 100644 --- a/xen/arch/x86/include/asm/debugger.h +++ b/xen/arch/x86/include/asm/debugger.h @@ -94,7 +94,7 @@ static inline bool debugger_trap_entry( =20 #ifdef CONFIG_GDBSX unsigned int dbg_rw_mem(unsigned long gva, XEN_GUEST_HANDLE_PARAM(void) bu= f, - unsigned int len, domid_t domid, bool toaddr, + unsigned int len, struct domain *d, bool toaddr, uint64_t pgd3); #endif =20 diff --git a/xen/common/domctl.c b/xen/common/domctl.c index 57135d4478..5879117580 100644 --- a/xen/common/domctl.c +++ b/xen/common/domctl.c @@ -308,7 +308,6 @@ long cf_check do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domc= tl_t) u_domctl) if ( op->domain =3D=3D DOMID_INVALID ) { case XEN_DOMCTL_createdomain: - case XEN_DOMCTL_gdbsx_guestmemio: d =3D NULL; break; } --=20 2.34.1