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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-08-21 14:31:24 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-08-21 14:45:33 -0400
commit806c312e50f122c47913145cf884f53dd09d9199 (patch)
treec6d64ccc297c5f8e9a2959365d74c877cde93894 /arch/x86/xen/enlighten.c
parent59b294403e9814e7c1154043567f0d71bac7a511 (diff)
xen/x86: Workaround 64-bit hypervisor and 32-bit initial domain.
If a 64-bit hypervisor is booted with a 32-bit initial domain, the hypervisor deals with the initial domain as "compat" and does some extra adjustments (like pagetables are 4 bytes instead of 8). It also adjusts the xen_start_info->pt_base incorrectly. When booted with a 32-bit hypervisor (32-bit initial domain): .. (XEN) Start info: cf831000->cf83147c (XEN) Page tables: cf832000->cf8b5000 .. [ 0.000000] PT: cf832000 (f832000) [ 0.000000] Reserving PT: f832000->f8b5000 And with a 64-bit hypervisor: (XEN) Start info: 00000000cf831000->00000000cf8314b4 (XEN) Page tables: 00000000cf832000->00000000cf8b6000 [ 0.000000] PT: cf834000 (f834000) [ 0.000000] Reserving PT: f834000->f8b8000 To deal with this, we keep keep track of the highest physical address we have reserved via memblock_reserve. If that address does not overlap with pt_base, we have a gap which we reserve. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch/x86/xen/enlighten.c')
-rw-r--r--arch/x86/xen/enlighten.c30
1 files changed, 21 insertions, 9 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index e532eb50e8d7..511f92d79e4a 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1002,19 +1002,24 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
* If the MFN is not in the m2p (provided to us by the hypervisor) this
* function won't do anything. In practice this means that the XenBus
* MFN won't be available for the initial domain. */
-static void __init xen_reserve_mfn(unsigned long mfn)
+static unsigned long __init xen_reserve_mfn(unsigned long mfn)
{
- unsigned long pfn;
+ unsigned long pfn, end_pfn = 0;
if (!mfn)
- return;
+ return end_pfn;
+
pfn = mfn_to_pfn(mfn);
- if (phys_to_machine_mapping_valid(pfn))
- memblock_reserve(PFN_PHYS(pfn), PAGE_SIZE);
+ if (phys_to_machine_mapping_valid(pfn)) {
+ end_pfn = PFN_PHYS(pfn) + PAGE_SIZE;
+ memblock_reserve(PFN_PHYS(pfn), end_pfn);
+ }
+ return end_pfn;
}
static void __init xen_reserve_internals(void)
{
unsigned long size;
+ unsigned long last_phys = 0;
if (!xen_pv_domain())
return;
@@ -1022,12 +1027,13 @@ static void __init xen_reserve_internals(void)
/* xen_start_info does not exist in the M2P, hence can't use
* xen_reserve_mfn. */
memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
+ last_phys = __pa(xen_start_info) + PAGE_SIZE;
- xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info));
- xen_reserve_mfn(xen_start_info->store_mfn);
+ last_phys = max(xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info)), last_phys);
+ last_phys = max(xen_reserve_mfn(xen_start_info->store_mfn), last_phys);
if (!xen_initial_domain())
- xen_reserve_mfn(xen_start_info->console.domU.mfn);
+ last_phys = max(xen_reserve_mfn(xen_start_info->console.domU.mfn), last_phys);
if (xen_feature(XENFEAT_auto_translated_physmap))
return;
@@ -1043,8 +1049,14 @@ static void __init xen_reserve_internals(void)
* a lot (and call memblock_reserve for each PAGE), so lets just use
* the easy way and reserve it wholesale. */
memblock_reserve(__pa(xen_start_info->mfn_list), size);
-
+ last_phys = max(__pa(xen_start_info->mfn_list) + size, last_phys);
/* The pagetables are reserved in mmu.c */
+
+ /* Under 64-bit hypervisor with a 32-bit domain, the hypervisor
+ * offsets the pt_base by two pages. Hence the reservation that is done
+ * in mmu.c misses two pages. We correct it here if we detect this. */
+ if (last_phys < __pa(xen_start_info->pt_base))
+ memblock_reserve(last_phys, __pa(xen_start_info->pt_base) - last_phys);
}
void xen_setup_shared_info(void)
{