Software Update: Xen 4.8.1/ 4.9.0 RC2

Xen is a baremetal hypervisor for the x86 and ARMv7/v8 platform and allows several operating systems to run simultaneously on a single system without drastically impacting performance. For more information about Xen and its community, please refer to this one and this one page. Currently, only Linux, NetBSD, and FreeBSD are supported as host systems, but work is underway to fully support other operating systems as well. The developers have released Xen 4.8.1 and 4.9.0 RC2, with the following announcements:

XenProject 4.8.1

We are pleased to announce the release of Xen 4.8.1. This is available immediately from its git repository (tag RELEASE-4.8.1) or from this download page This release contains the following bug-fixes and improvements in the Xen Project hypervisor:

• update Xen version to 4.8.1
• oxenstored: trim history in the frequent_ops function
• oxenstored transaction conflicts: improve logging
• oxenstored: don’t wake to issue no conflict-credit
• oxenstored: do not commit read-only transactions
• oxenstored: allow self-conflicts
• oxenstored: blame the connection that caused a transaction conflict
• oxenstored: track commit history
• oxenstored: discard old commit-history on txn end
• oxenstored: only record operations with side-effects in history
• oxenstored: support commit history tracking
• oxenstored: add transaction info relevant to history-tracking
• oxenstored: ignore domains with no conflict-credit
• oxenstored: handling of domain conflict-credit
• oxenstored: comments explaining some variables
• xenstored: Log when the write transaction rate limit bites
• xenstored: apply a write transaction rate limit
• tools/libxenctrl: fix error check after opening libxenforeignmemory
• libxl: correct xenstore entry for empty cdrom
• x86: use 64 bit mask when masking away mfn bits
• memory: properly check guest memory ranges in XENMEM_exchange handling
• xen: sched: don’t call hooks of the wrong scheduler via VCPU2OP
• x86/EFI: avoid Xen image when looking for module/kexec position
• x86/EFI: avoid IOMMU faults on [_end,__2M_rwdata_end)
• x86/EFI: avoid overrunning mb_modules[]
• build/clang: fix XSM dummy policy when using clang 4.0
• x86: drop unneeded __packed attributes
• arm: xen_size should be paddr_t for consistency
• xen/arm: alternative: Register re-mapped Xen area as a temporary virtual region
• QEMU_TAG update
• arm: read/write rank->vcpu atomically
• xen/arm: p2m: Perform local TLB invalidation on vCPU migration
• xen/arm: Introduce INVALID_VCPU_ID
• xen/arm: Set nr_cpu_ids to available number of cpus
• xen/arm: acpi: Relax hw domain mapping attributes to p2m_mmio_direct_c
• Revert “xen/arm: Map mmio-sram nodes as un-cached memory”
• xen/arm: dt: Relax hw domain mapping attributes to p2m_mmio_direct_c
• xen/arm: flush icache as well when XEN_DOMCTL_cacheflush is issued
• xen/arm: fix GIC_INVALID_LR
• fix out of bound access to mode_strings
• missing vgic_unlock_rank in gic_remove_irq_from_guest
• xen/arm: Fix macro for ARM Jazelle CPU feature identification
• xen/arm: traps: Emulate ICC_SRE_EL1 as RAZ/WI
• xen/arm: Fix misplaced parentheses for PSCI version check
• arm/irq: Reorder check when the IRQ is already used by someone
• Don’t clear HCR_VM bit when updating VTTBR.
• x86/emul: Correct the decoding of mov to/from cr/dr
• x86emul: correct decoding of vzero{all,upper}
• xen: credit2: don’t miss accounting while doing a credit reset.
• xen: credit2: always mark a tickled pCPU as… tickled!
• x86/layout: Correct Xen’s idea of ​​its own memory layout
• x86/vmx: Don’t leak host syscall MSR state into HVM guests
• xen/arm: fix affected memory range by dcache clean functions
• xen/arm: introduce vwfi parameter
• arm/p2m: remove the page from p2m->pages list before freeing it
• QEMU_TAG update
• VMX: fix VMCS race on context-switch paths
• xen/p2m: Fix p2m_flush_table for non-nested cases
• x86/ept: allow write-combining on !mfn_valid() MMIO mappings again
• IOMMU: always call teardown callback
• x86/emulate: don’t assume that addr_size == 32 implies protected mode
• xen: credit2: fix shutdown/suspend when playing with cpupools.
• xen: credit2: never consider CPUs outside of our cpupool.
• xen: credit2: use the correct scratch cpumask.
• x86/hvm: do not set msr_tsc_adjust on hvm_set_guest_tsc_fixed
• x86emul: correct FPU stub asm() constraints
• x86: segment attribute handling adjustments
• x86emul: LOCK check adjustments
• x86emul: VEX.B is ignored in compatibility mode
• x86/xstate: Fix array overrun on hardware with LWP
• arm/p2m: Fix regression during domain shutdown with active mem_access
• libxl: fix libxl_set_memory_target
• xen/arm: gic-v3: Make sure read from ICC_IAR1_EL1 is visible on the redistributor
• x86/cpu: Don’t update this_cpu for get_cpu_vendor(, gcv_guest)
• x86/emul: Correct the return value handling of VMFUNC
• x86/boot: fix build with certain older gcc versions
• x86emul: CMPXCHG16B requires an aligned operand
• VT-d: correct dma_msi_set_affinity()
• x86emul: ignore most segment bases for 64-bit mode in is_aligned()
• x86emul: MOVNTI does not allow REP prefixes
• x86/VPMU: clear the overflow status of which counter happened to overflow
• x86/hvm: don’t unconditionally create a default ioreq server
• dragonfly: section index 0 is special
• x86emul: CMPXCHG{8,16}B ignore prefixes
• xen: Fix determining when domain creation is complete
• x86emul: correct PUSHF/POPF
• init/FreeBSD: fix incorrect usage of $rc_pids in xendriverdomain
• init/FreeBSD: add rc control variables
• init/FreeBSD: fix xencommons so it can only be launched by Dom0
• init/FreeBSD: remove xendriverdomain_precmd
• init/FreeBSD: set correct PATH for xl devd
• xsm: allow relevant permission during migrate and gpu passthrough.
• libxl: init_acpi_config should return rc in exit path, and set to 0 on success
• x86/emul: add likely()/unlikely() to test harness
• x86/HVM: add missing NULL check before using VMFUNC hook
• x86: force EFLAGS.IF on when exiting to PV guests
• x86/emul: Correct the handling of flags with SYSCALL
• QEMU_TAG update
• update Xen version to 4.8.1-pre

In addition, this release also contains the following fixes to qemu-traditional:

• cirrus/vnc: zap drop bitblit support from console code.
• cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo
• cirrus: fix oob access issue (CVE-2017-2615)
• qemu: ioport_read, ioport_write: be defensive about 32-bit addresses

This release also contains changes to qemu-upstream, whose changelogs we do not list here as it contains many changes that are not directly releated to the Xen Project Hypervisor and thus this release. However, you can check (between tags qemu-xen-4.8.0 and qemu-xen-4.8.1).

Xen 4.9 RC2

Hi all,
Xen 4.9 RC2 is tagged. You can check that out from xen.git:
git://xenbits.xen.org/xen.git 4.9.0-rc2
For your convenience there is also a tarball at:

And the signature is at:
.sig
Please send bug reports and test reports to xen-devel@xxxxxxxxxxxxxxxxxxx. When sending bug reports, please CC relevant maintainers and me (julien.grall@xxxxxxx).
thanks,
Julien Gral