[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2] nested VMX: fix I/O port exit emulation
>>> On 04.12.13 at 02:51, "Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx> wrote: > Jan Beulich wrote on 2013-12-03: >> @@ -2220,15 +2219,23 @@ int nvmx_n2_vmexit_handler(struct cpu_us >> if ( ctrl & CPU_BASED_ACTIVATE_IO_BITMAP ) >> { >> unsigned long qual; >> - u16 port; >> + u16 port, size; >> >> __vmread(EXIT_QUALIFICATION, &qual); >> port = qual >> 16; >> - bitmap = nvmx->iobitmap[port >> 15]; >> - if ( bitmap[(port & 0x7fff) >> 3] & (1 << (port & 0x7)) ) >> - nvcpu->nv_vmexit_pending = 1; >> + size = (qual & 7) + 1; >> + do { >> + const u8 *bitmap = nvmx->iobitmap[port >> 15]; >> + >> + if ( bitmap[(port & 0x7fff) >> 3] & (1 << (port & 7)) ) >> + nvcpu->nv_vmexit_pending = 1; >> + if ( !--size ) >> + break; >> + if ( !++port ) >> + nvcpu->nv_vmexit_pending = 1; > > If port overflow, will it cause vmexit or maybe other fault like GP or just > be ignored? The documentation is explicit here: It causes a VM exit. And hence the emulation is doing so too. > Also, you need to check the DF bit to know the string direction > before updating the port. I think Andrew already sufficiently clarified that part. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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