[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH RFC 1/2] xen/pvh: take the p2m lock when doing logdirty ops from HVM domains
Due to locking order, the p2m lock must be taken before the paging lock, or else the following panic occurs when trying to use logdirty ops from a PVH Dom0: (XEN) mm locking order violation: 292 > 222 (XEN) Xen BUG at mm-locks.h:140 (XEN) ----[ Xen-4.5-unstable x86_64 debug=y Not tainted ]---- (XEN) CPU: 1 (XEN) RIP: e008:[<ffff82d0801e9ea5>] get_page_from_gfn_p2m+0xb0/0x286 (XEN) RFLAGS: 0000000000010282 CONTEXT: hypervisor (XEN) rax: 0000000000000000 rbx: ffff83019a1f7884 rcx: 0000000000000000 (XEN) rdx: ffff83019a1f0000 rsi: 000000000000000a rdi: ffff82d0802926c0 (XEN) rbp: ffff83019a1f77f8 rsp: ffff83019a1f7798 r8: ffff83019e830000 (XEN) r9: 0000000000000003 r10: 00000000000000de r11: 0000000000000003 (XEN) r12: ffff83019a1f77c4 r13: ffff83019a138820 r14: ffff83019a1f7974 (XEN) r15: 0000000000057431 cr0: 0000000080050033 cr4: 00000000000026f0 (XEN) cr3: 000000019ea86000 cr2: 000000080205d000 (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008 [...] (XEN) Xen call trace: (XEN) [<ffff82d0801e9ea5>] get_page_from_gfn_p2m+0xb0/0x286 (XEN) [<ffff82d0802223e9>] hap_p2m_ga_to_gfn_4_levels+0x59/0x2b7 (XEN) [<ffff82d080222663>] hap_gva_to_gfn_4_levels+0x1c/0x29 (XEN) [<ffff82d0801edf67>] paging_gva_to_gfn+0xb8/0xce (XEN) [<ffff82d0801b9bc0>] clear_user_hvm+0xd7/0x324 (XEN) [<ffff82d0801e8776>] paging_log_dirty_op+0x358/0x552 (XEN) [<ffff82d0801e8d47>] paging_domctl+0x140/0x177 (XEN) [<ffff82d08015ccca>] arch_do_domctl+0x212/0x269e (XEN) [<ffff82d08010487c>] do_domctl+0x195d/0x1cd1 (XEN) [<ffff82d0801bafba>] hvm_do_hypercall+0x1b8/0x31c (XEN) [<ffff82d0801e0d3f>] vmx_vmexit_handler+0xf91/0x1a5f (XEN) [<ffff82d0801e7a51>] vmx_asm_vmexit_handler+0x41/0xc0 (XEN) (XEN) (XEN) **************************************** (XEN) Panic on CPU 1: (XEN) Xen BUG at mm-locks.h:140 (XEN) **************************************** (XEN) (XEN) Reboot in five seconds... Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx> Cc: Tim Deegan <tim@xxxxxxx> Cc: Jan Beulich <jbeulich@xxxxxxxx> --- xen/arch/x86/mm/paging.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c index 6b788f7..5af6309 100644 --- a/xen/arch/x86/mm/paging.c +++ b/xen/arch/x86/mm/paging.c @@ -412,6 +412,8 @@ static int paging_log_dirty_op(struct domain *d, if ( !resuming ) domain_pause(d); + if (has_hvm_container_vcpu(current)) + p2m_lock(p2m_get_hostp2m(current->domain)); paging_lock(d); if ( !d->arch.paging.preempt.dom ) @@ -421,6 +423,8 @@ static int paging_log_dirty_op(struct domain *d, d->arch.paging.preempt.op != sc->op ) { paging_unlock(d); + if (has_hvm_container_vcpu(current)) + p2m_unlock(p2m_get_hostp2m(current->domain)); ASSERT(!resuming); domain_unpause(d); return -EBUSY; @@ -533,6 +537,8 @@ static int paging_log_dirty_op(struct domain *d, } paging_unlock(d); + if (has_hvm_container_vcpu(current)) + p2m_unlock(p2m_get_hostp2m(current->domain)); if ( rv ) { @@ -555,6 +561,8 @@ static int paging_log_dirty_op(struct domain *d, out: d->arch.paging.preempt.dom = NULL; paging_unlock(d); + if (has_hvm_container_vcpu(current)) + p2m_unlock(p2m_get_hostp2m(current->domain)); domain_unpause(d); if ( l1 ) -- 1.9.3 (Apple Git-50) _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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