[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 8/9] xen/arm: Implement hypercall for dirty page tracing
On 10/04/2013 05:44 AM, Jaeyong Yoo wrote: > Add hypercall (shadow op: enable/disable and clean/peek dirted page bitmap). > It consists of two parts: dirty page detecting and saving. > For detecting, we setup the guest p2m's leaf PTE read-only and whenever > the guest tries to write something, permission fault happens and traps into > xen. > The permission-faulted GPA should be saved for the toolstack (when it wants > to see > which pages are dirted). For this purpose, we temporarily save the GPAs into > linked > list by using 'add_mapped_vaddr' function and when toolstack wants > (log_dirty_op function) the GPAs are copied into bitmap and the linnked list > is flushed. > > Additionally, for supporting parallel migration of domUs, vlpt area should be > context > switched. > > Signed-off-by: Jaeyong Yoo <jaeyong.yoo@xxxxxxxxxxx> > --- [..] > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c > index 4c0fc32..3b78ed2 100644 > --- a/xen/arch/arm/traps.c > +++ b/xen/arch/arm/traps.c > @@ -1313,6 +1313,8 @@ static void do_trap_data_abort_guest(struct > cpu_user_regs *regs, > const char *msg; > int rc, level = -1; > mmio_info_t info; > + int page_fault = ((dabt.dfsc & FSC_MASK) == > + (FSC_FLT_PERM + FSC_3D_LEVEL) && dabt.write); > > if ( !check_conditional_instr(regs, hsr) ) > { > @@ -1327,22 +1329,23 @@ static void do_trap_data_abort_guest(struct > cpu_user_regs *regs, > info.gva = READ_SYSREG64(FAR_EL2); > #endif > > - if (dabt.s1ptw) > + if ( dabt.s1ptw && !page_fault ) I think checking !page_fault is nearly everywhere is error-prone when this function will be modified. Can you do something like this? if ( page_fault ) // Your code to handle page fault else { // handle_mmio } It will avoid && !page_fault. > goto bad_data_abort; > > rc = gva_to_ipa(info.gva, &info.gpa); > - if ( rc == -EFAULT ) > + if ( rc == -EFAULT && !page_fault ) > goto bad_data_abort; > > /* XXX: Decode the instruction if ISS is not valid */ > - if ( !dabt.valid ) > + if ( !dabt.valid && !page_fault ) > goto bad_data_abort; > > /* > * Erratum 766422: Thumb store translation fault to Hypervisor may > * not have correct HSR Rt value. > */ > - if ( cpu_has_erratum_766422() && (regs->cpsr & PSR_THUMB) && dabt.write ) > + if ( cpu_has_erratum_766422() && (regs->cpsr & PSR_THUMB) && dabt.write > + && !page_fault) > { > rc = decode_instruction(regs, &info.dabt); > if ( rc ) > @@ -1358,6 +1361,16 @@ static void do_trap_data_abort_guest(struct > cpu_user_regs *regs, > return; > } > > + /* handle permission fault on write */ > + if ( page_fault ) > + { > + if ( current->domain->arch.dirty.mode == 0 ) > + goto bad_data_abort; > + > + handle_page_fault(current->domain, info.gpa); You must call advance_pc(regs, hsr) here. > + return; > + } > + > bad_data_abort: -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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