[Xen-devel] [PATCH v13 12/19] xen/pvh: Update E820 to work with PVH (v2)

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

From: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>

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.

Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 arch/x86/xen/setup.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 2137c51..dd5f905 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"
 
@@ -81,6 +82,9 @@ 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);
@@ -103,6 +107,7 @@ 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;
 
@@ -116,7 +121,7 @@ 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;
                }
@@ -154,6 +159,13 @@ static unsigned long __init xen_do_chunk(unsigned long 
start,
 static unsigned long __init xen_release_chunk(unsigned long start,
                                              unsigned long end)
 {
+       /*
+        * Xen already ballooned out the E820 non RAM regions for us
+        * and set them up properly in EPT.
+        */
+       if (xen_feature(XENFEAT_auto_translated_physmap))
+               return end - start;
+
        return xen_do_chunk(start, end, true);
 }
 
@@ -222,7 +234,13 @@ static void __init xen_set_identity_and_release_chunk(
         * (except for the ISA region which must be 1:1 mapped) to
         * release the refcounts (in Xen) on the original frames.
         */
-       for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) {
+
+       /*
+        * PVH E820 matches the hypervisor's P2M which means we need to
+        * account for the proper values of *release and *identity.
+        */
+       for (pfn = start_pfn; !xen_feature(XENFEAT_auto_translated_physmap) &&
+            pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) {
                pte_t pte = __pte_ma(0);
 
                if (pfn < PFN_UP(ISA_END_ADDRESS))
-- 
1.8.3.1


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