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Date: Mon, 22 Oct 2012 11:57:17 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Stefano Stabellini <stefano.stabellini@...citrix.com>
Cc: "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, 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:
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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