Commit 61f01dd941 ("x86_64, asm: Work around AMD SYSRET SS descriptor
attribute issue") makes AMD processors set SS to __KERNEL_DS in
__switch_to() to deal with cases when SS is NULL.
This breaks Xen PV guests who do not want to load SS with__KERNEL_DS.
Since the problem that the commit is trying to address would have to be
fixed in the hypervisor (if it in fact exists under Xen) there is no
reason to set X86_BUG_SYSRET_SS_ATTRS flag for PV VPCUs here.
This can be easily achieved by adding x86_hyper_xen_hvm.set_cpu_features
op which will clear this flag. (And since this structure is no longer
HVM-specific we should do some renaming).
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Pull xen features and fixes from David Vrabel:
- use a single source list of hypercalls, generating other tables etc.
at build time.
- add a "Xen PV" APIC driver to support >255 VCPUs in PV guests.
- significant performance improve to guest save/restore/migration.
- scsiback/front save/restore support.
- infrastructure for multi-page xenbus rings.
- misc fixes.
* tag 'stable/for-linus-4.1-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/pci: Try harder to get PXM information for Xen
xenbus_client: Extend interface to support multi-page ring
xen-pciback: also support disabling of bus-mastering and memory-write-invalidate
xen: support suspend/resume in pvscsi frontend
xen: scsiback: add LUN of restored domain
xen-scsiback: define a pr_fmt macro with xen-pvscsi
xen/mce: fix up xen_late_init_mcelog() error handling
xen/privcmd: improve performance of MMAPBATCH_V2
xen: unify foreign GFN map/unmap for auto-xlated physmap guests
x86/xen/apic: WARN with details.
x86/xen: Provide a "Xen PV" APIC driver to support >255 VCPUs
xen/pciback: Don't print scary messages when unsupported by hypervisor.
xen: use generated hypercall symbols in arch/x86/xen/xen-head.S
xen: use generated hypervisor symbols in arch/x86/xen/trace.c
xen: synchronize include/xen/interface/xen.h with xen
xen: build infrastructure for generating hypercall depending symbols
xen: balloon: Use static attribute groups for sysfs entries
xen: pcpu: Use static attribute groups for sysfs entry
Instead of mangling the default APIC driver, provide a Xen PV guest
specific one that explicitly provides appropriate methods.
This allows use to report that all APIC IDs are valid, allowing dom0
to boot with more than 255 VCPUs.
Since the probe order of APIC drivers is link dependent, we add in an
late probe function to change to the Xen PV if it hadn't been done
during bootup.
Suggested-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Cathy Avery <cathy.avery@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Commit 1e02ce4ccc ("x86: Store a per-cpu shadow copy of CR4")
introduced CR4 shadows.
These shadows are initialized in early boot code. The commit missed
initialization for 64-bit PV(H) guests that this patch adds.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Commit d524165cb8 ("x86/apic: Check x2apic early") tests X2APIC_ENABLE
bit of MSR_IA32_APICBASE when CONFIG_X86_X2APIC is off and panics
the kernel when this bit is set.
Xen's PV guests will pass this MSR read to the hypervisor which will
return its version of the MSR, where this bit might be set. Make sure
we clear it before returning MSR value to the caller.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Pull xen bug fixes from David Vrabel:
"Several critical linear p2m fixes that prevented some hosts from
booting"
* tag 'stable/for-linus-3.19-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen: properly retrieve NMI reason
xen: check for zero sized area when invalidating memory
xen: use correct type for physical addresses
xen: correct race in alloc_p2m_pmd()
xen: correct error for building p2m list on 32 bits
x86/xen: avoid freeing static 'name' when kasprintf() fails
x86/xen: add extra memory for remapped frames during setup
x86/xen: don't count how many PFNs are identity mapped
x86/xen: Free bootmem in free_p2m_page() during early boot
x86/xen: Remove unnecessary BUG_ON(preemptible()) in xen_setup_timer()
Using the native code here can't work properly, as the hypervisor would
normally have cleared the two reason bits by the time Dom0 gets to see
the NMI (if passed to it at all). There's a shared info field for this,
and there's an existing hook to use - just fit the two together. This
is particularly relevant so that NMIs intended to be handled by APEI /
GHES actually make it to the respective handler.
Note that the hook can (and should) be used irrespective of whether
being in Dom0, as accessing port 0x61 in a DomU would be even worse,
while the shared info field would just hold zero all the time. Note
further that hardware NMI handling for PVH doesn't currently work
anyway due to missing code in the hypervisor (but it is expected to
work the native rather than the PV way).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The 3 level p2m tree for the Xen tools is constructed very early at
boot by calling xen_build_mfn_list_list(). Memory needed for this tree
is allocated via extend_brk().
As this tree (other than the kernel internal p2m tree) is only needed
for domain save/restore, live migration and crash dump analysis it
doesn't matter whether it is constructed very early or just some
milliseconds later when memory allocation is possible by other means.
This patch moves the call of xen_build_mfn_list_list() just after
calling xen_pagetable_p2m_copy() simplifying this function, too, as it
doesn't have to bother with two parallel trees now. The same applies
for some other internal functions.
While simplifying code, make early_can_reuse_p2m_middle() static and
drop the unused second parameter. p2m_mid_identity_mfn can be removed
as well, it isn't used either.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Pull percpu consistent-ops changes from Tejun Heo:
"Way back, before the current percpu allocator was implemented, static
and dynamic percpu memory areas were allocated and handled separately
and had their own accessors. The distinction has been gone for many
years now; however, the now duplicate two sets of accessors remained
with the pointer based ones - this_cpu_*() - evolving various other
operations over time. During the process, we also accumulated other
inconsistent operations.
This pull request contains Christoph's patches to clean up the
duplicate accessor situation. __get_cpu_var() uses are replaced with
with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().
Unfortunately, the former sometimes is tricky thanks to C being a bit
messy with the distinction between lvalues and pointers, which led to
a rather ugly solution for cpumask_var_t involving the introduction of
this_cpu_cpumask_var_ptr().
This converts most of the uses but not all. Christoph will follow up
with the remaining conversions in this merge window and hopefully
remove the obsolete accessors"
* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
irqchip: Properly fetch the per cpu offset
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
Revert "powerpc: Replace __get_cpu_var uses"
percpu: Remove __this_cpu_ptr
clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
sparc: Replace __get_cpu_var uses
avr32: Replace __get_cpu_var with __this_cpu_write
blackfin: Replace __get_cpu_var uses
tile: Use this_cpu_ptr() for hardware counters
tile: Replace __get_cpu_var uses
powerpc: Replace __get_cpu_var uses
alpha: Replace __get_cpu_var
ia64: Replace __get_cpu_var uses
s390: cio driver &__get_cpu_var replacements
s390: Replace __get_cpu_var uses
mips: Replace __get_cpu_var uses
MIPS: Replace __get_cpu_var uses in FPU emulator.
arm: Replace __this_cpu_ptr with raw_cpu_ptr
...
This fixes two bugs in PVH guests:
- Not setting EFER.NX means the NX bit in page table entries is
ignored on Intel processors and causes reserved bit page faults on
AMD processors.
- After the Xen commit 7645640d6ff1 ("x86/PVH: don't set EFER_SCE for
pvh guest") PVH guests are required to set EFER.SCE to enable the
SYSCALL instruction.
Secondary VCPUs are started with pagetables with the NX bit set so
EFER.NX must be set before using any stack or data segment.
xen_pvh_cpu_early_init() is the new secondary VCPU entry point that
sets EFER before jumping to cpu_bringup_and_idle().
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Size restrictions native kernels wouldn't have resulted from the initrd
getting mapped into the initial mapping. The kernel doesn't really need
the initrd to be mapped, so use infrastructure available in Xen to avoid
the mapping and hence the restriction.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The _PAGE_IO_MAP PTE flag was only used by Xen PV guests to mark PTEs
that were used to map I/O regions that are 1:1 in the p2m. This
allowed Xen to obtain the correct PFN when converting the MFNs read
from a PTE back to their PFN.
Xen guests no longer use _PAGE_IOMAP for this. Instead mfn_to_pfn()
returns the correct PFN by using a combination of the m2p and p2m to
determine if an MFN corresponds to a 1:1 mapping in the the p2m.
Remove _PAGE_IOMAP, replacing it with _PAGE_UNUSED2 to allow for
future uses of the PTE flag.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x). This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.
Other use cases are for storing and retrieving data from the current
processors percpu area. __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.
__get_cpu_var() is defined as :
#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.
this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.
This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset. Thereby address calculations are avoided and less registers
are used when code is generated.
Transformations done to __get_cpu_var()
1. Determine the address of the percpu instance of the current processor.
DEFINE_PER_CPU(int, y);
int *x = &__get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(&y);
2. Same as #1 but this time an array structure is involved.
DEFINE_PER_CPU(int, y[20]);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
3. Retrieve the content of the current processors instance of a per cpu
variable.
DEFINE_PER_CPU(int, y);
int x = __get_cpu_var(y)
Converts to
int x = __this_cpu_read(y);
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(&x, this_cpu_ptr(&y), sizeof(x));
5. Assignment to a per cpu variable
DEFINE_PER_CPU(int, y)
__get_cpu_var(y) = x;
Converts to
__this_cpu_write(y, x);
6. Increment/Decrement etc of a per cpu variable
DEFINE_PER_CPU(int, y);
__get_cpu_var(y)++
Converts to
__this_cpu_inc(y)
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull Xen updates from David Vrabel:
- remove unused V2 grant table support
- note that Konrad is xen-blkkback/front maintainer
- add 'xen_nopv' option to disable PV extentions for x86 HVM guests
- misc minor cleanups
* tag 'stable/for-linus-3.17-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen-pciback: Document the 'quirks' sysfs file
xen/pciback: Fix error return code in xen_pcibk_attach()
xen/events: drop negativity check of unsigned parameter
xen/setup: Remove Identity Map Debug Message
xen/events/fifo: remove a unecessary use of BM()
xen/events/fifo: ensure all bitops are properly aligned even on x86
xen/events/fifo: reset control block and local HEADs on resume
xen/arm: use BUG_ON
xen/grant-table: remove support for V2 tables
x86/xen: safely map and unmap grant frames when in atomic context
MAINTAINERS: Make me the Xen block subsystem (front and back) maintainer
xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests.
Pull EFI changes from Ingo Molnar:
"Main changes in this cycle are:
- arm64 efi stub fixes, preservation of FP/SIMD registers across
firmware calls, and conversion of the EFI stub code into a static
library - Ard Biesheuvel
- Xen EFI support - Daniel Kiper
- Support for autoloading the efivars driver - Lee, Chun-Yi
- Use the PE/COFF headers in the x86 EFI boot stub to request that
the stub be loaded with CONFIG_PHYSICAL_ALIGN alignment - Michael
Brown
- Consolidate all the x86 EFI quirks into one file - Saurabh Tangri
- Additional error logging in x86 EFI boot stub - Ulf Winkelvos
- Support loading initrd above 4G in EFI boot stub - Yinghai Lu
- EFI reboot patches for ACPI hardware reduced platforms"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
efi/arm64: Handle missing virtual mapping for UEFI System Table
arch/x86/xen: Silence compiler warnings
xen: Silence compiler warnings
x86/efi: Request desired alignment via the PE/COFF headers
x86/efi: Add better error logging to EFI boot stub
efi: Autoload efivars
efi: Update stale locking comment for struct efivars
arch/x86: Remove efi_set_rtc_mmss()
arch/x86: Replace plain strings with constants
xen: Put EFI machinery in place
xen: Define EFI related stuff
arch/x86: Remove redundant set_bit(EFI_MEMMAP) call
arch/x86: Remove redundant set_bit(EFI_SYSTEM_TABLES) call
efi: Introduce EFI_PARAVIRT flag
arch/x86: Do not access EFI memory map if it is not available
efi: Use early_mem*() instead of early_io*()
arch/ia64: Define early_memunmap()
x86/reboot: Add EFI reboot quirk for ACPI Hardware Reduced flag
efi/reboot: Allow powering off machines using EFI
efi/reboot: Add generic wrapper around EfiResetSystem()
...
Compiler complains in the following way when x86 32-bit kernel
with Xen support is build:
CC arch/x86/xen/enlighten.o
arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’:
arch/x86/xen/enlighten.c:1726:3: warning: right shift count >= width of type [enabled by default]
Such line contains following EFI initialization code:
boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
There is no issue if x86 64-bit kernel is build. However, 32-bit case
generate warning (even if that code will not be executed because Xen
does not work on 32-bit EFI platforms) due to __pa() returning unsigned long
type which has 32-bits width. So move whole EFI initialization stuff
to separate function and build it conditionally to avoid above mentioned
warning on x86 32-bit architecture.
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This patch enables EFI usage under Xen dom0. Standard EFI Linux
Kernel infrastructure cannot be used because it requires direct
access to EFI data and code. However, in dom0 case it is not possible
because above mentioned EFI stuff is fully owned and controlled
by Xen hypervisor. In this case all calls from dom0 to EFI must
be requested via special hypercall which in turn executes relevant
EFI code in behalf of dom0.
When dom0 kernel boots it checks for EFI availability on a machine.
If it is detected then artificial EFI system table is filled.
Native EFI callas are replaced by functions which mimics them
by calling relevant hypercall. Later pointer to EFI system table
is passed to standard EFI machinery and it continues EFI subsystem
initialization taking into account that there is no direct access
to EFI boot services, runtime, tables, structures, etc. After that
system runs as usual.
This patch is based on Jan Beulich and Tang Liang work.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Tang Liang <liang.tang@oracle.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
By default when CONFIG_XEN and CONFIG_XEN_PVHVM kernels are
run, they will enable the PV extensions (drivers, interrupts, timers,
etc) - which is the best option for the majority of use cases.
However, in some cases (kexec not fully working, benchmarking)
we want to disable Xen PV extensions. As such introduce the
'xen_nopv' parameter that will do it.
This parameter is intended only for HVM guests as the Xen PV
guests MUST boot with PV extensions. However, even if you use
'xen_nopv' on Xen PV guests it will be ignored.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
---
[v2: s/off/xen_nopv/ per Boris Ostrovsky recommendation.]
[v3: Add Reviewed-by]
[v4: Clarify that this is only for HVM guests]
Pull Xen fixes from David Vrabel:
"Xen regression and PVH fixes for 3.16-rc1
- fix dom0 PVH memory setup on latest unstable Xen releases
- fix 64-bit x86 PV guest boot failure on Xen 3.1 and earlier
- fix resume regression on non-PV (auto-translated physmap) guests"
* tag 'stable/for-linus-3.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/grant-table: fix suspend for non-PV guests
x86/xen: no need to explicitly register an NMI callback
Revert "xen/pvh: Update E820 to work with PVH (v2)"
x86/xen: fix memory setup for PVH dom0
Since af06d66ee32b (x86: fix setup of PVH Dom0 memory map) in Xen, PVH
dom0 need only use the memory memory provided by Xen which has already
setup all the correct holes.
xen_memory_setup() then ends up being trivial for a PVH guest so
introduce a new function (xen_auto_xlated_memory_setup()).
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Tested-by: Roger Pau Monné <roger.pau@citrix.com>
Pull Xen updates from David Vrabel:
"xen: features and fixes for 3.16-rc0
- support foreign mappings in PVH domains (needed when dom0 is PVH)
- fix mapping high MMIO regions in x86 PV guests (this is also the
first half of removing the PAGE_IOMAP PTE flag).
- ARM suspend/resume support.
- ARM multicall support"
* tag 'stable/for-linus-3.16-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen: map foreign pfns for autotranslated guests
xen-acpi-processor: Don't display errors when we get -ENOSYS
xen/pciback: Document the entry points for 'pcistub_put_pci_dev'
xen/pciback: Document when the 'unbind' and 'bind' functions are called.
xen-pciback: Document when we FLR an PCI device.
xen-pciback: First reset, then free.
xen-pciback: Cleanup up pcistub_put_pci_dev
x86/xen: do not use _PAGE_IOMAP in xen_remap_domain_mfn_range()
x86/xen: set regions above the end of RAM as 1:1
x86/xen: only warn once if bad MFNs are found during setup
x86/xen: compactly store large identity ranges in the p2m
x86/xen: fix set_phys_range_identity() if pfn_e > MAX_P2M_PFN
x86/xen: rename early_p2m_alloc() and early_p2m_alloc_middle()
xen/x86: set panic notifier priority to minimum
arm,arm64/xen: introduce HYPERVISOR_suspend()
xen: refactor suspend pre/post hooks
arm: xen: export HYPERVISOR_multicall to modules.
arm64: introduce virt_to_pfn
arm/xen: Remove definiition of virt_to_pfn in asm/xen/page.h
arm: xen: implement multicall hypercall support.
Execution is not going to continue after telling Xen about the crash.
Let other panic notifiers run by postponing the final hypercall as much
as possible.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Boris Ostrovsky
Linus Torvalds
Konrad Rzeszutek Wilk
Andy Lutomirski
Jan Beulich
Juergen Gross
Mukesh Rathor
David Vrabel
Christoph Lameter
Daniel Kiper
Radim Krčmář