[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86/HVM: refuse doing string operations in certain situations
On Fri, Sep 20, 2013 at 02:08:45PM +0100, Jan Beulich wrote: > We shouldn't do any acceleration for > - "rep movs" when either side is passed through MMIO or when both sides > are handled by qemu > - "rep ins" and "rep outs" when the memory operand is any kind of MMIO Could you explain this in a bit more details? Why is acceleration in those cases bad? Thanks. > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > > --- a/xen/arch/x86/hvm/emulate.c > +++ b/xen/arch/x86/hvm/emulate.c > @@ -686,6 +686,7 @@ static int hvmemul_rep_ins( > unsigned long addr; > uint32_t pfec = PFEC_page_present | PFEC_write_access; > paddr_t gpa; > + p2m_type_t p2mt; > int rc; > > rc = hvmemul_virtual_to_linear( > @@ -702,6 +703,10 @@ static int hvmemul_rep_ins( > if ( rc != X86EMUL_OKAY ) > return rc; > > + (void) get_gfn_query_unlocked(current->domain, gpa >> PAGE_SHIFT, &p2mt); > + if ( p2mt == p2m_mmio_direct || p2mt == p2m_mmio_dm ) > + return X86EMUL_UNHANDLEABLE; > + > return hvmemul_do_pio(src_port, reps, bytes_per_rep, gpa, IOREQ_READ, > !!(ctxt->regs->eflags & X86_EFLAGS_DF), NULL); > } > @@ -719,6 +724,7 @@ static int hvmemul_rep_outs( > unsigned long addr; > uint32_t pfec = PFEC_page_present; > paddr_t gpa; > + p2m_type_t p2mt; > int rc; > > rc = hvmemul_virtual_to_linear( > @@ -735,6 +741,10 @@ static int hvmemul_rep_outs( > if ( rc != X86EMUL_OKAY ) > return rc; > > + (void) get_gfn_query_unlocked(current->domain, gpa >> PAGE_SHIFT, &p2mt); > + if ( p2mt == p2m_mmio_direct || p2mt == p2m_mmio_dm ) > + return X86EMUL_UNHANDLEABLE; > + > return hvmemul_do_pio(dst_port, reps, bytes_per_rep, gpa, IOREQ_WRITE, > !!(ctxt->regs->eflags & X86_EFLAGS_DF), NULL); > } > @@ -787,6 +797,10 @@ static int hvmemul_rep_movs( > (void) get_gfn_query_unlocked(current->domain, sgpa >> PAGE_SHIFT, > &sp2mt); > (void) get_gfn_query_unlocked(current->domain, dgpa >> PAGE_SHIFT, > &dp2mt); > > + if ( sp2mt == p2m_mmio_direct || dp2mt == p2m_mmio_direct || > + (sp2mt == p2m_mmio_dm && dp2mt == p2m_mmio_dm) ) > + return X86EMUL_UNHANDLEABLE; > + > if ( sp2mt == p2m_mmio_dm ) > return hvmemul_do_mmio( > sgpa, reps, bytes_per_rep, dgpa, IOREQ_READ, df, NULL); > > > > x86/HVM: refuse doing string operations in certain situations > > We shouldn't do any acceleration for > - "rep movs" when either side is passed through MMIO or when both sides > are handled by qemu > - "rep ins" and "rep outs" when the memory operand is any kind of MMIO > > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> > > --- a/xen/arch/x86/hvm/emulate.c > +++ b/xen/arch/x86/hvm/emulate.c > @@ -686,6 +686,7 @@ static int hvmemul_rep_ins( > unsigned long addr; > uint32_t pfec = PFEC_page_present | PFEC_write_access; > paddr_t gpa; > + p2m_type_t p2mt; > int rc; > > rc = hvmemul_virtual_to_linear( > @@ -702,6 +703,10 @@ static int hvmemul_rep_ins( > if ( rc != X86EMUL_OKAY ) > return rc; > > + (void) get_gfn_query_unlocked(current->domain, gpa >> PAGE_SHIFT, &p2mt); > + if ( p2mt == p2m_mmio_direct || p2mt == p2m_mmio_dm ) > + return X86EMUL_UNHANDLEABLE; > + > return hvmemul_do_pio(src_port, reps, bytes_per_rep, gpa, IOREQ_READ, > !!(ctxt->regs->eflags & X86_EFLAGS_DF), NULL); > } > @@ -719,6 +724,7 @@ static int hvmemul_rep_outs( > unsigned long addr; > uint32_t pfec = PFEC_page_present; > paddr_t gpa; > + p2m_type_t p2mt; > int rc; > > rc = hvmemul_virtual_to_linear( > @@ -735,6 +741,10 @@ static int hvmemul_rep_outs( > if ( rc != X86EMUL_OKAY ) > return rc; > > + (void) get_gfn_query_unlocked(current->domain, gpa >> PAGE_SHIFT, &p2mt); > + if ( p2mt == p2m_mmio_direct || p2mt == p2m_mmio_dm ) > + return X86EMUL_UNHANDLEABLE; > + > return hvmemul_do_pio(dst_port, reps, bytes_per_rep, gpa, IOREQ_WRITE, > !!(ctxt->regs->eflags & X86_EFLAGS_DF), NULL); > } > @@ -787,6 +797,10 @@ static int hvmemul_rep_movs( > (void) get_gfn_query_unlocked(current->domain, sgpa >> PAGE_SHIFT, > &sp2mt); > (void) get_gfn_query_unlocked(current->domain, dgpa >> PAGE_SHIFT, > &dp2mt); > > + if ( sp2mt == p2m_mmio_direct || dp2mt == p2m_mmio_direct || > + (sp2mt == p2m_mmio_dm && dp2mt == p2m_mmio_dm) ) > + return X86EMUL_UNHANDLEABLE; > + > if ( sp2mt == p2m_mmio_dm ) > return hvmemul_do_mmio( > sgpa, reps, bytes_per_rep, dgpa, IOREQ_READ, df, NULL); > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxx > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |