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>
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@ -1002,19 +1002,24 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
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* If the MFN is not in the m2p (provided to us by the hypervisor) this
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* function won't do anything. In practice this means that the XenBus
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* MFN won't be available for the initial domain. */
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static void __init xen_reserve_mfn(unsigned long mfn)
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static unsigned long __init xen_reserve_mfn(unsigned long mfn)
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{
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unsigned long pfn;
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unsigned long pfn, end_pfn = 0;
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if (!mfn)
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return;
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return end_pfn;
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pfn = mfn_to_pfn(mfn);
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if (phys_to_machine_mapping_valid(pfn))
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memblock_reserve(PFN_PHYS(pfn), PAGE_SIZE);
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if (phys_to_machine_mapping_valid(pfn)) {
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end_pfn = PFN_PHYS(pfn) + PAGE_SIZE;
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memblock_reserve(PFN_PHYS(pfn), end_pfn);
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}
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return end_pfn;
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}
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static void __init xen_reserve_internals(void)
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{
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unsigned long size;
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unsigned long last_phys = 0;
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if (!xen_pv_domain())
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return;
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@ -1022,12 +1027,13 @@ static void __init xen_reserve_internals(void)
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/* xen_start_info does not exist in the M2P, hence can't use
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* xen_reserve_mfn. */
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memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
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last_phys = __pa(xen_start_info) + PAGE_SIZE;
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xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info));
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xen_reserve_mfn(xen_start_info->store_mfn);
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last_phys = max(xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info)), last_phys);
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last_phys = max(xen_reserve_mfn(xen_start_info->store_mfn), last_phys);
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if (!xen_initial_domain())
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xen_reserve_mfn(xen_start_info->console.domU.mfn);
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last_phys = max(xen_reserve_mfn(xen_start_info->console.domU.mfn), last_phys);
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if (xen_feature(XENFEAT_auto_translated_physmap))
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return;
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@ -1043,8 +1049,14 @@ static void __init xen_reserve_internals(void)
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* a lot (and call memblock_reserve for each PAGE), so lets just use
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* the easy way and reserve it wholesale. */
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memblock_reserve(__pa(xen_start_info->mfn_list), size);
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last_phys = max(__pa(xen_start_info->mfn_list) + size, last_phys);
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/* The pagetables are reserved in mmu.c */
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/* Under 64-bit hypervisor with a 32-bit domain, the hypervisor
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* offsets the pt_base by two pages. Hence the reservation that is done
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* in mmu.c misses two pages. We correct it here if we detect this. */
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if (last_phys < __pa(xen_start_info->pt_base))
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memblock_reserve(last_phys, __pa(xen_start_info->pt_base) - last_phys);
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}
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void xen_setup_shared_info(void)
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{
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