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Message-ID: <alpine.DEB.2.02.1210231406490.2689@kaball.uk.xensource.com>
Date: Tue, 23 Oct 2012 14:07:06 +0100
From: Stefano Stabellini <stefano.stabellini@...citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: Stefano Stabellini <Stefano.Stabellini@...citrix.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
"mukesh.rathor@...cle.com" <mukesh.rathor@...cle.com>,
Ian Campbell <Ian.Campbell@...rix.com>
Subject: Re: [PATCH 4/6] xen/pvh: bootup and setup related changes.
On Mon, 22 Oct 2012, Konrad Rzeszutek Wilk wrote:
> On Mon, Oct 22, 2012 at 02:34:44PM +0100, Stefano Stabellini wrote:
> > On Sat, 20 Oct 2012, Konrad Rzeszutek Wilk wrote:
> > > From: Mukesh Rathor <mukesh.rathor@...cle.com>
> > >
> > > In enlighten.c for PVH we can trap cpuid via vmexit, so don't
> > > need to use emulated prefix call. We also check for vector callback
> > > early on, as it is a required feature. PVH also runs at default kernel
> > > IOPL.
> > >
> > > In setup.c, in xen_add_extra_mem() we can skip updating P2M as it's managed
> > > by Xen. PVH maps the entire IO space, but only RAM pages need to be repopulated.
> > >
> > > Finally, pure PV settings are moved to a separate function that is only called
> > > for pure PV, ie, pv with pvmmu.
> > >
> > > Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> > >
> > > diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> > > index 8971a26..8cce47b 100644
> > > --- a/arch/x86/xen/setup.c
> > > +++ b/arch/x86/xen/setup.c
> > > @@ -27,6 +27,7 @@
> > > #include <xen/interface/memory.h>
> > > #include <xen/interface/physdev.h>
> > > #include <xen/features.h>
> > > +#include "mmu.h"
> > > #include "xen-ops.h"
> > > #include "vdso.h"
> > >
> > > @@ -78,6 +79,9 @@ static void __init xen_add_extra_mem(u64 start, u64 size)
> > >
> > > memblock_reserve(start, size);
> > >
> > > + if (xen_feature(XENFEAT_auto_translated_physmap))
> > > + return;
> > > +
> > > xen_max_p2m_pfn = PFN_DOWN(start + size);
> > > for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) {
> > > unsigned long mfn = pfn_to_mfn(pfn);
> > > @@ -100,6 +104,7 @@ static unsigned long __init xen_do_chunk(unsigned long start,
> > > .domid = DOMID_SELF
> > > };
> > > unsigned long len = 0;
> > > + int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);
> > > unsigned long pfn;
> > > int ret;
> > >
> > > @@ -113,7 +118,7 @@ static unsigned long __init xen_do_chunk(unsigned long start,
> > > continue;
> > > frame = mfn;
> > > } else {
> > > - if (mfn != INVALID_P2M_ENTRY)
> > > + if (!xlated_phys && mfn != INVALID_P2M_ENTRY)
> > > continue;
> > > frame = pfn;
> > > }
> >
> > Shouldn't we add a "!xlated_phys &&" to the other case as well?
>
> No. That is handled in xen_pvh_identity_map_chunk which
> just does a xen_set_clr_mmio_pvh_pte call for the "released"
> pages. But that is a bit of ... well, extra logic. I think
> if we did this it would work and look much nicer:
Yes, I think that this version looks better
>
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index 8cce47b..b451a77 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -114,9 +114,15 @@ static unsigned long __init xen_do_chunk(unsigned long start,
>
> if (release) {
> /* Make sure pfn exists to start with */
> - if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
> + if (mfn == INVALID_P2M_ENTRY || (!xlated_phys && (mfn_to_pfn(mfn) != pfn)))
> continue;
> frame = mfn;
> + /* The hypercall PHYSDEVOP_map_iomem to release memory has already
> + * happend, so we just do a nop here. */
> + if (xlated_phys) {
> + len++;
> + continue;
> + }
> } else {
> if (!xlated_phys && mfn != INVALID_P2M_ENTRY)
> continue;
> @@ -219,15 +225,24 @@ static void __init xen_set_identity_and_release_chunk(
> {
> unsigned long pfn;
>
> + /* For PVH, the pfns [0..MAX] are mapped to mfn's in the EPT/NPT. The mfns
> + * are released as part of this 1:1 mapping hypercall back to the dom heap.
> + * Also, we map the entire IO space, ie, beyond max_pfn_mapped.
> + */
> + int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);
> +
> /*
> * If the PFNs are currently mapped, the VA mapping also needs
> * to be updated to be 1:1.
> */
> - for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
> - (void)HYPERVISOR_update_va_mapping(
> - (unsigned long)__va(pfn << PAGE_SHIFT),
> - mfn_pte(pfn, PAGE_KERNEL_IO), 0);
> -
> + for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) {
> + if (xlated_phys)
> + xen_set_clr_mmio_pvh_pte(pfn, pfn, 1 /* one pfn */, 1 /* add mapping */);
> + else
> + (void)HYPERVISOR_update_va_mapping(
> + (unsigned long)__va(pfn << PAGE_SHIFT),
> + mfn_pte(pfn, PAGE_KERNEL_IO), 0);
> + }
> if (start_pfn < nr_pages)
> *released += xen_release_chunk(
> start_pfn, min(end_pfn, nr_pages));
> @@ -235,27 +250,6 @@ static void __init xen_set_identity_and_release_chunk(
> *identity += set_phys_range_identity(start_pfn, end_pfn);
> }
>
> -/* For PVH, the pfns [0..MAX] are mapped to mfn's in the EPT/NPT. The mfns
> - * are released as part of this 1:1 mapping hypercall back to the dom heap.
> - * Also, we map the entire IO space, ie, beyond max_pfn_mapped.
> - */
> -static void __init xen_pvh_identity_map_chunk(unsigned long start_pfn,
> - unsigned long end_pfn, unsigned long *released,
> - unsigned long *identity, unsigned long max_pfn)
> -{
> - unsigned long pfn;
> - int numpfns = 1, add_mapping = 1;
> -
> - for (pfn = start_pfn; pfn < end_pfn; pfn++)
> - xen_set_clr_mmio_pvh_pte(pfn, pfn, numpfns, add_mapping);
> -
> - if (start_pfn <= max_pfn) {
> - unsigned long end = min(max_pfn_mapped, end_pfn);
> - *released += end - start_pfn;
> - }
> - *identity += end_pfn - start_pfn;
> -}
> -
> static unsigned long __init xen_set_identity_and_release(
> const struct e820entry *list, size_t map_size, unsigned long nr_pages)
> {
> @@ -286,17 +280,10 @@ static unsigned long __init xen_set_identity_and_release(
> if (entry->type == E820_RAM)
> end_pfn = PFN_UP(entry->addr);
>
> - if (start_pfn < end_pfn) {
> - if (xlated_phys) {
> - xen_pvh_identity_map_chunk(start_pfn,
> - end_pfn, &released, &identity,
> - nr_pages);
> - } else {
> - xen_set_identity_and_release_chunk(
> + if (start_pfn < end_pfn)
> + xen_set_identity_and_release_chunk(
> start_pfn, end_pfn, nr_pages,
> &released, &identity);
> - }
> - }
> start = end;
> }
> }
>
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