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2009-09-10KVM: Return to userspace on emulation failureAvi Kivity
Instead of mindlessly retrying to execute the instruction, report the failure to userspace. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Use macro to iterate over vcpus.Gleb Natapov
[christian: remove unused variables on s390] Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Break dependency between vcpu index in vcpus array and vcpu_id.Gleb Natapov
Archs are free to use vcpu_id as they see fit. For x86 it is used as vcpu's apic id. New ioctl is added to configure boot vcpu id that was assumed to be 0 till now. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Use pointer to vcpu instead of vcpu_id in timer code.Gleb Natapov
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Introduce kvm_vcpu_is_bsp() function.Gleb Natapov
Use it instead of open code "vcpu_id zero is BSP" assumption. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: s/shadow_pte/spte/Avi Kivity
We use shadow_pte and spte inconsistently, switch to the shorter spelling. Rename set_shadow_pte() to __set_spte() to avoid a conflict with the existing set_spte(), and to indicate its lowlevelness. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: Adjust pte accessors to explicitly indicate guest or shadow pteAvi Kivity
Since the guest and host ptes can have wildly different format, adjust the pte accessor names to indicate on which type of pte they operate on. No functional changes. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: Fix is_dirty_pte()Avi Kivity
is_dirty_pte() is used on guest ptes, not shadow ptes, so it needs to avoid shadow_dirty_mask and use PT_DIRTY_MASK instead. Misdetecting dirty pages could lead to unnecessarily setting the dirty bit under EPT. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: VMX: Move rmode structure to vmx-specific codeAvi Kivity
rmode is only used in vmx, so move it to vmx.c Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: VMX: Support Unrestricted Guest featureNitin A Kamble
"Unrestricted Guest" feature is added in the VMX specification. Intel Westmere and onwards processors will support this feature. It allows kvm guests to run real mode and unpaged mode code natively in the VMX mode when EPT is turned on. With the unrestricted guest there is no need to emulate the guest real mode code in the vm86 container or in the emulator. Also the guest big real mode code works like native. The attached patch enhances KVM to use the unrestricted guest feature if available on the processor. It also adds a new kernel/module parameter to disable the unrestricted guest feature at the boot time. Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: switch irq injection/acking data structures to irq_lockMarcelo Tosatti
Protect irq injection/acking data structures with a separate irq_lock mutex. This fixes the following deadlock: CPU A CPU B kvm_vm_ioctl_deassign_dev_irq() mutex_lock(&kvm->lock); worker_thread() -> kvm_deassign_irq() -> kvm_assigned_dev_interrupt_work_handler() -> deassign_host_irq() mutex_lock(&kvm->lock); -> cancel_work_sync() [blocked] [gleb: fix ia64 path] Reported-by: Alex Williamson <alex.williamson@hp.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Grab pic lock in kvm_pic_clear_isr_ackMarcelo Tosatti
isr_ack is protected by kvm_pic->lock. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Cleanup LAPIC interfaceJan Kiszka
None of the interface services the LAPIC emulation provides need to be exported to modules, and kvm_lapic_get_base is even totally unused today. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: VMX: Fix reporting of unhandled EPT violationsAvi Kivity
Instead of returning -ENOTSUPP, exit normally but indicate the hardware exit reason. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Cache pdptrsAvi Kivity
Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx, guest memory access on svm) extract them on demand. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: VMX: Simplify pdptr and cr3 managementAvi Kivity
Instead of reading the PDPTRs from memory after every exit (which is slow and wrong, as the PDPTRs are stored on the cpu), sync the PDPTRs from memory to the VMCS before entry, and from the VMCS to memory after exit. Do the same for cr3. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: VMX: Avoid duplicate ept tlb flush when setting cr3Avi Kivity
vmx_set_cr3() will call vmx_tlb_flush(), which will flush the ept context. So there is no need to call ept_sync_context() explicitly. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: do not register i8254 PIO regions until we are initializedGregory Haskins
We currently publish the i8254 resources to the pio_bus before the devices are fully initialized. Since we hold the pit_lock, its probably not a real issue. But lets clean this up anyway. Reported-by: Avi Kivity <avi@redhat.com> Signed-off-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: cleanup io_device codeGregory Haskins
We modernize the io_device code so that we use container_of() instead of dev->private, and move the vtable to a separate ops structure (theoretically allows better caching for multiple instances of the same ops structure) Signed-off-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: SVM: Fold kvm_svm.h info svm.cAvi Kivity
kvm_svm.h is only included from svm.c, so fold it in. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: SVM: use explicit 64bit storage for sysenter valuesAndre Przywara
Since AMD does not support sysenter in 64bit mode, the VMCB fields storing the MSRs are truncated to 32bit upon VMRUN/#VMEXIT. So store the values in a separate 64bit storage to avoid truncation. [andre: fix amd->amd migration] Signed-off-by: Christoph Egger <christoph.egger@amd.com> Signed-off-by: Andre Przywara <andre.przywara@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Allow PIT emulation without speaker portJan Kiszka
The in-kernel speaker emulation is only a dummy and also unneeded from the performance point of view. Rather, it takes user space support to generate sound output on the host, e.g. console beeps. To allow this, introduce KVM_CREATE_PIT2 which controls in-kernel speaker port emulation via a flag passed along the new IOCTL. It also leaves room for future extensions of the PIT configuration interface. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: irqfdGregory Haskins
KVM provides a complete virtual system environment for guests, including support for injecting interrupts modeled after the real exception/interrupt facilities present on the native platform (such as the IDT on x86). Virtual interrupts can come from a variety of sources (emulated devices, pass-through devices, etc) but all must be injected to the guest via the KVM infrastructure. This patch adds a new mechanism to inject a specific interrupt to a guest using a decoupled eventfd mechnanism: Any legal signal on the irqfd (using eventfd semantics from either userspace or kernel) will translate into an injected interrupt in the guest at the next available interrupt window. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Move common KVM Kconfig items to new file virt/kvm/KconfigAvi Kivity
Reduce Kconfig code duplication. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Drop interrupt shadow when single stepping should be done only on VMXGleb Natapov
The problem exists only on VMX. Also currently we skip this step if there is pending exception. The patch fixes this too. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: cleanup arch/x86/kvm/MakefileChristoph Hellwig
Use proper foo-y style list additions to cleanup all the conditionals, move module selection after compound object selection and remove the superflous comment. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: x86 emulator: fix jmp far decoding (opcode 0xea)Avi Kivity
The jump target should not be sign extened; use an unsigned decode flag. Cc: stable@kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: x86 emulator: Implement zero-extended immediate decodingAvi Kivity
Absolute jumps use zero extended immediate operands. Cc: stable@kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: fix cpuid E2BIG handling for extended request typesMark McLoughlin
If we run out of cpuid entries for extended request types we should return -E2BIG, just like we do for the standard request types. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Use MSR names in place of addressJaswinder Singh Rajput
Replace 0xc0010010 with MSR_K8_SYSCFG and 0xc0010015 with MSR_K7_HWCR. Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Add MCE supportHuang Ying
The related MSRs are emulated. MCE capability is exported via extension KVM_CAP_MCE and ioctl KVM_X86_GET_MCE_CAP_SUPPORTED. A new vcpu ioctl command KVM_X86_SETUP_MCE is used to setup MCE emulation such as the mcg_cap. MCE is injected via vcpu ioctl command KVM_X86_SET_MCE. Extended machine-check state (MCG_EXT_P) and CMCI are not implemented. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Replace MSR_IA32_TIME_STAMP_COUNTER with MSR_IA32_TSC of msr-index.hJaswinder Singh Rajput
Use standard msr-index.h's MSR declaration. MSR_IA32_TSC is better than MSR_IA32_TIME_STAMP_COUNTER as it also solves 80 column issue. Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: VMX: Properly handle software interrupt re-injection in real modeGleb Natapov
When reinjecting a software interrupt or exception, use the correct instruction length provided by the hardware instead of a hardcoded 1. Fixes problems running the suse 9.1 livecd boot loader. Problem introduced by commit f0a3602c20 ("KVM: Move interrupt injection logic to x86.c"). Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-26x86: Fix vSMP boot crashYinghai Lu
2.6.31-rc7 does not boot on vSMP systems: [ 8.501108] CPU31: Thermal monitoring enabled (TM1) [ 8.501127] CPU 31 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8 [ 8.650254] CPU31: Intel(R) Xeon(R) CPU E5540 @ 2.53GHz stepping 04 [ 8.710324] Brought up 32 CPUs [ 8.713916] Total of 32 processors activated (162314.96 BogoMIPS). [ 8.721489] ERROR: parent span is not a superset of domain->span [ 8.727686] ERROR: domain->groups does not contain CPU0 [ 8.733091] ERROR: groups don't span domain->span [ 8.737975] ERROR: domain->cpu_power not set [ 8.742416] Ravikiran Thirumalai bisected it to: | commit 2759c3287de27266e06f1f4e82cbd2d65f6a044c | x86: don't call read_apic_id if !cpu_has_apic The problem is that on vSMP systems the CPUID derived initial-APICIDs are overlapping - so we need to fall back on hard_smp_processor_id() which reads the local APIC. Both come from the hardware (influenced by firmware though) so it's a tough call which one to trust. Doing the quirk expresses the vSMP property properly and also does not affect other systems, so we go for this solution instead of a revert. Reported-and-Tested-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Shai Fultheim <shai@scalex86.org> Cc: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <4A944D3C.5030100@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-25x86, xen: Initialize cx to suppress warningH. Peter Anvin
Initialize cx before calling xen_cpuid(), in order to suppress the "may be used uninitialized in this function" warning. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
2009-08-25x86, xen: Suppress WP test on XenJeremy Fitzhardinge
Xen always runs on CPUs which properly support WP enforcement in privileged mode, so there's no need to test for it. This also works around a crash reported by Arnd Hannemann, though I think its just a band-aid for that case. Reported-by: Arnd Hannemann <hannemann@nets.rwth-aachen.de> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-08-25Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clockevent: Prevent dead lock on clockevents_lock timers: Drop write permission on /proc/timer_list
2009-08-25Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix build with older binutils and consolidate linker script x86: Fix an incorrect argument of reserve_bootmem() x86: add vmlinux.lds to targets in arch/x86/boot/compressed/Makefile xen: rearrange things to fix stackprotector x86: make sure load_percpu_segment has no stackprotector i386: Fix section mismatches for init code with !HOTPLUG_CPU x86, pat: Allow ISA memory range uncacheable mapping requests
2009-08-25x86: Fix build with older binutils and consolidate linker scriptJan Beulich
binutils prior to 2.17 can't deal with the currently possible situation of a new segment following the per-CPU segment, but that new segment being empty - objcopy misplaces the .bss (and perhaps also the .brk) sections outside of any segment. However, the current ordering of sections really just appears to be the effect of cumulative unrelated changes; re-ordering things allows to easily guarantee that the segment following the per-CPU one is non-empty, and at once eliminates the need for the bogus data.init2 segment. Once touching this code, also use the various data section helper macros from include/asm-generic/vmlinux.lds.h. -v2: fix !SMP builds. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: <sam@ravnborg.org> LKML-Reference: <4A94085D02000078000119A5@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-24x86: Fix an incorrect argument of reserve_bootmem()Amerigo Wang
This line looks suspicious, because if this is true, then the 'flags' parameter of function reserve_bootmem_generic() will be unused when !CONFIG_NUMA. I don't think this is what we want. Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: akpm@linux-foundation.org LKML-Reference: <20090821083709.5098.52505.sendpatchset@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-21x86: don't call '->send_IPI_mask()' with an empty maskLinus Torvalds
As noted in 83d349f35e1ae72268c5104dbf9ab2ae635425d4 ("x86: don't send an IPI to the empty set of CPU's"), some APIC's will be very unhappy with an empty destination mask. That commit added a WARN_ON() for that case, and avoided the resulting problem, but didn't fix the underlying reason for why those empty mask cases happened. This fixes that, by checking the result of 'cpumask_andnot()' of the current CPU actually has any other CPU's left in the set of CPU's to be sent a TLB flush, and not calling down to the IPI code if the mask is empty. The reason this started happening at all is that we started passing just the CPU mask pointers around in commit 4595f9620 ("x86: change flush_tlb_others to take a const struct cpumask"), and when we did that, the cpumask was no longer thread-local. Before that commit, flush_tlb_mm() used to create it's own copy of 'mm->cpu_vm_mask' and pass that copy down to the low-level flush routines after having tested that it was not empty. But after changing it to just pass down the CPU mask pointer, the lower level TLB flush routines would now get a pointer to that 'mm->cpu_vm_mask', and that could still change - and become empty - after the test due to other CPU's having flushed their own TLB's. See http://bugzilla.kernel.org/show_bug.cgi?id=13933 for details. Tested-by: Thomas Björnell <thomas.bjornell@gmail.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-21x86: don't send an IPI to the empty set of CPU'sLinus Torvalds
The default_send_IPI_mask_logical() function uses the "flat" APIC mode to send an IPI to a set of CPU's at once, but if that set happens to be empty, some older local APIC's will apparently be rather unhappy. So just warn if a caller gives us an empty mask, and ignore it. This fixes a regression in 2.6.30.x, due to commit 4595f9620 ("x86: change flush_tlb_others to take a const struct cpumask"), documented here: http://bugzilla.kernel.org/show_bug.cgi?id=13933 which causes a silent lock-up. It only seems to happen on PPro, P2, P3 and Athlon XP cores. Most developers sadly (or not so sadly, if you're a developer..) have more modern CPU's. Also, on x86-64 we don't use the flat APIC mode, so it would never trigger there even if the APIC didn't like sending an empty IPI mask. Reported-by: Pavel Vilim <wylda@volny.cz> Reported-and-tested-by: Thomas Björnell <thomas.bjornell@gmail.com> Reported-and-tested-by: Martin Rogge <marogge@onlinehome.de> Cc: Mike Travis <travis@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-20x86: add vmlinux.lds to targets in arch/x86/boot/compressed/MakefileJan Beulich
The absence of vmlinux.lds here keeps .vmlinux.lds.cmd from being included, which in turn leads to it and all its dependents always getting rebuilt independent of whether they are already up-to-date. Signed-off-by: Jan Beulich <jbeulich@novell.com> LKML-Reference: <4A8D84670200007800010D31@vpn.id2.novell.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-08-20Merge branch 'bugfix' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen into x86/urgent
2009-08-19xen: rearrange things to fix stackprotectorJeremy Fitzhardinge
Make sure the stack-protector segment registers are properly set up before calling any functions which may have stack-protection compiled into them. [ Impact: prevent Xen early-boot crash when stack-protector is enabled ] Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-08-19x86: make sure load_percpu_segment has no stackprotectorJeremy Fitzhardinge
load_percpu_segment() is used to set up the per-cpu segment registers, which are also used for -fstack-protector. Make sure that the load_percpu_segment() function doesn't have stackprotector enabled. [ Impact: allow percpu setup before calling stack-protected functions ] Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-08-19clockevent: Prevent dead lock on clockevents_lockSuresh Siddha
Currently clockevents_notify() is called with interrupts enabled at some places and interrupts disabled at some other places. This results in a deadlock in this scenario. cpu A holds clockevents_lock in clockevents_notify() with irqs enabled cpu B waits for clockevents_lock in clockevents_notify() with irqs disabled cpu C doing set_mtrr() which will try to rendezvous of all the cpus. This will result in C and A come to the rendezvous point and waiting for B. B is stuck forever waiting for the spinlock and thus not reaching the rendezvous point. Fix the clockevents code so that clockevents_lock is taken with interrupts disabled and thus avoid the above deadlock. Also call lapic_timer_propagate_broadcast() on the destination cpu so that we avoid calling smp_call_function() in the clockevents notifier chain. This issue left us wondering if we need to change the MTRR rendezvous logic to use stop machine logic (instead of smp_call_function) or add a check in spinlock debug code to see if there are other spinlocks which gets taken under both interrupts enabled/disabled conditions. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com> Cc: "Brown Len" <len.brown@intel.com> LKML-Reference: <1250544899.2709.210.camel@sbs-t61.sc.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-18Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: use the right flag for get_vm_area() percpu, sparc64: fix sparse possible cpu map handling init: set nr_cpu_ids before setup_per_cpu_areas()
2009-08-18i386: Fix section mismatches for init code with !HOTPLUG_CPUJan Beulich
Commit 0e83815be719d3391bf5ea24b7fe696c07dbd417 changed the section the initial_code variable gets allocated in, in an attempt to address a section conflict warning. This, however created a new section conflict when building without HOTPLUG_CPU. The apparently only (reasonable) way to address this is to always use __REFDATA. Once at it, also fix a second section mismatch when not using HOTPLUG_CPU. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Robert Richter <robert.richter@amd.com> LKML-Reference: <4A8AE7CD020000780001054B@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-17x86, pat: Allow ISA memory range uncacheable mapping requestsSuresh Siddha
Max Vozeler reported: > Bug 13877 - bogl-term broken with CONFIG_X86_PAT=y, works with =n > > strace of bogl-term: > 814 mmap2(NULL, 65536, PROT_READ|PROT_WRITE, MAP_SHARED, 4, 0) > = -1 EAGAIN (Resource temporarily unavailable) > 814 write(2, "bogl: mmaping /dev/fb0: Resource temporarily unavailable\n", > 57) = 57 PAT code maps the ISA memory range as WB in the PAT attribute, so that fixed range MTRR registers define the actual memory type (UC/WC/WT etc). But the upper level is_new_memtype_allowed() API checks are failing, as the request here is for UC and the return tracked type is WB (Tracked type is WB as MTRR type for this legacy range potentially will be different for each 4k page). Fix is_new_memtype_allowed() by always succeeding the ISA address range checks, as the null PAT (WB) and def MTRR fixed range register settings satisfy the memory type needs of the applications that map the ISA address range. Reported-and-Tested-by: Max Vozeler <xam@debian.org> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>