Hi Wei,
On 03/09/2018 05:29 PM, Wei Liu wrote:
On Mon, Mar 05, 2018 at 07:38:36AM -0700, Jan Beulich wrote:
On 05.03.18 at 15:11, <julien.gr...@arm.com> wrote:
On 05/03/18 14:00, Jan Beulich wrote:
On 05.03.18 at 14:43, <julien.gr...@arm.com> wrote:
Anyway, I don't have much knowledge on the x86 to make the modification
that you suggested. So I am going to revert to _mfn(0) for x86.
I'd prefer if you didn't, but well, it'll be one of us to clean it up
then.
I can keep as INVALID_MFN. But then either you or Andrew (or anyone x86
folks) would have to provide the patch to skip incrementing invalid MFN
(if I understood correctly your request).
Sigh - this should go together imo. While wrongly incrementing from
zero was bad, wrongly wrapping from INVALID_MFN makes things
worse.
Try this patch?
I am happy to carry this patch at the beginning of my series if you want.
---8<---
From 8f0024c690c736d17adde0fa765cbbf6fa2846dc Mon Sep 17 00:00:00 2001
From: Wei Liu <wei.l...@citrix.com>
Date: Fri, 9 Mar 2018 17:20:14 +0000
Subject: [PATCH] x86/mm: skip incrementing mfn if it is not a valid mfn
The function is called to fill in page table entries in
populate_pt_range. Skip incrementing mfn if it is invalid.
Signed-off-by: Wei Liu <wei.l...@citrix.com>
---
xen/arch/x86/mm.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 9b559448a7..5f5577c7c2 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4731,7 +4731,8 @@ int map_pages_to_xen(
}
virt += 1UL << L3_PAGETABLE_SHIFT;
- mfn += 1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT);
+ if ( !mfn_eq(_mfn(mfn), INVALID_MFN) )
+ mfn += 1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT);
nr_mfns -= 1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT);
continue;
}
@@ -4756,7 +4757,8 @@ int map_pages_to_xen(
if ( i > nr_mfns )
i = nr_mfns;
virt += i << PAGE_SHIFT;
- mfn += i;
+ if ( !mfn_eq(_mfn(mfn), INVALID_MFN) )
+ mfn += i;
nr_mfns -= i;
continue;
}
@@ -4824,7 +4826,8 @@ int map_pages_to_xen(
}
virt += 1UL << L2_PAGETABLE_SHIFT;
- mfn += 1UL << PAGETABLE_ORDER;
+ if ( !mfn_eq(_mfn(mfn), INVALID_MFN) )
+ mfn += 1UL << PAGETABLE_ORDER;
nr_mfns -= 1UL << PAGETABLE_ORDER;
}
else
@@ -4853,7 +4856,8 @@ int map_pages_to_xen(
if ( i > nr_mfns )
i = nr_mfns;
virt += i << L1_PAGETABLE_SHIFT;
- mfn += i;
+ if ( !mfn_eq(_mfn(mfn), INVALID_MFN) )
+ mfn += i;
nr_mfns -= i;
goto check_l3;
}
@@ -4898,7 +4902,8 @@ int map_pages_to_xen(
}
virt += 1UL << L1_PAGETABLE_SHIFT;
- mfn += 1UL;
+ if ( !mfn_eq(_mfn(mfn), INVALID_MFN) )
+ mfn += 1UL;
nr_mfns -= 1UL;
if ( (flags == PAGE_HYPERVISOR) &&
Cheers,
--
Julien Grall
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