> -----Original Message----- > From: Roger Pau Monné <[email protected]> > Sent: 17 February 2020 11:41 > To: Wei Liu <[email protected]> > Cc: Durrant, Paul <[email protected]>; Xen Development List <xen- > [email protected]>; Michael Kelley <[email protected]>; Wei > Liu <[email protected]>; Jan Beulich <[email protected]>; Andrew Cooper > <[email protected]> > Subject: Re: [PATCH v2 2/3] x86/hyperv: skeleton for L0 assisted TLB flush > > On Mon, Feb 17, 2020 at 11:34:41AM +0000, Wei Liu wrote: > > On Fri, Feb 14, 2020 at 04:55:44PM +0000, Durrant, Paul wrote: > > > > -----Original Message----- > > > > From: Wei Liu <[email protected]> On Behalf Of Wei Liu > > > > Sent: 14 February 2020 13:34 > > > > To: Xen Development List <[email protected]> > > > > Cc: Michael Kelley <[email protected]>; Durrant, Paul > > > > <[email protected]>; Wei Liu <[email protected]>; Wei Liu > > > > <[email protected]>; Jan Beulich <[email protected]>; Andrew Cooper > > > > <[email protected]>; Roger Pau Monné <[email protected]> > > > > Subject: [PATCH v2 2/3] x86/hyperv: skeleton for L0 assisted TLB > flush > > > > > > > > Implement a basic hook for L0 assisted TLB flush. The hook needs to > > > > check if prerequisites are met. If they are not met, it returns an > error > > > > number to fall back to native flushes. > > > > > > > > Introduce a new variable to indicate if hypercall page is ready. > > > > > > > > Signed-off-by: Wei Liu <[email protected]> > > > > --- > > > > xen/arch/x86/guest/hyperv/Makefile | 1 + > > > > xen/arch/x86/guest/hyperv/hyperv.c | 17 ++++++++++++ > > > > xen/arch/x86/guest/hyperv/private.h | 4 +++ > > > > xen/arch/x86/guest/hyperv/tlb.c | 41 > +++++++++++++++++++++++++++++ > > > > 4 files changed, 63 insertions(+) > > > > create mode 100644 xen/arch/x86/guest/hyperv/tlb.c > > > > > > > > diff --git a/xen/arch/x86/guest/hyperv/Makefile > > > > b/xen/arch/x86/guest/hyperv/Makefile > > > > index 68170109a9..18902c33e9 100644 > > > > --- a/xen/arch/x86/guest/hyperv/Makefile > > > > +++ b/xen/arch/x86/guest/hyperv/Makefile > > > > @@ -1 +1,2 @@ > > > > obj-y += hyperv.o > > > > +obj-y += tlb.o > > > > diff --git a/xen/arch/x86/guest/hyperv/hyperv.c > > > > b/xen/arch/x86/guest/hyperv/hyperv.c > > > > index 70f4cd5ae0..f9d1f11ae3 100644 > > > > --- a/xen/arch/x86/guest/hyperv/hyperv.c > > > > +++ b/xen/arch/x86/guest/hyperv/hyperv.c > > > > @@ -33,6 +33,8 @@ DEFINE_PER_CPU_READ_MOSTLY(void *, hv_input_page); > > > > DEFINE_PER_CPU_READ_MOSTLY(void *, hv_vp_assist); > > > > DEFINE_PER_CPU_READ_MOSTLY(unsigned int, hv_vp_index); > > > > > > > > +static bool __read_mostly hv_hcall_page_ready; > > > > + > > > > static uint64_t generate_guest_id(void) > > > > { > > > > union hv_guest_os_id id = {}; > > > > @@ -119,6 +121,8 @@ static void __init setup_hypercall_page(void) > > > > BUG_ON(!hypercall_msr.enable); > > > > > > > > set_fixmap_x(FIX_X_HYPERV_HCALL, mfn << PAGE_SHIFT); > > > > > > Shouldn't this have at least a compiler barrier here? > > > > > > > OK. I will add a write barrier here. > > Hm, shouldn't such barrier be part of set_fixmap_x itself? >
Not really, for the purpose I had in mind. The hv_hcall_page_ready global is specific to this code and we need to make sure the page is actually ready before the code says it is. Paul > Note that map_pages_to_xen already performs atomic writes. > > Roger. _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
