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Xen

Xen is an open-source virtualization hypervisor.

www.xenproject.org

Yesterday's Activity

x86/idle: Fix buggy "x86/mwait-idle: enable interrupts before C1 on Xeons"
Andrew Cooper: The check of this_softirq_pending must be performed with irqs disabled, but this property was broken by an attempt to optimise entry/exit latency.

x86/idle: Implement a new MWAIT IPI-elision algorithm
Andrew Cooper: In order elide IPIs, we must be able to identify whether a target CPU is in MWAIT at the point it is woken up.

x86/idle: Remove broken MWAIT implementation
Andrew Cooper: cpuidle_wakeup_mwait() is a TOCTOU race.

Recent Activity

x86/idle: Fix buggy "x86/mwait-idle: enable interrupts before C1 on Xeons"
Andrew Cooper: The check of this_softirq_pending must be performed with irqs disabled, but this property was broken by an attempt to optimise entry/exit latency.

x86/idle: Implement a new MWAIT IPI-elision algorithm
Andrew Cooper: In order elide IPIs, we must be able to identify whether a target CPU is in MWAIT at the point it is woken up.

x86/idle: Remove broken MWAIT implementation
Andrew Cooper: cpuidle_wakeup_mwait() is a TOCTOU race.

drivers/pci: Add minor comment for maximum capability constant
Frediano Ziglio: The comment is similar to extended capabilities in the function below.

Activity Earlier In The Year

x86/intel: workaround several MONITOR/MWAIT errata
Roger Pau Monne: There are several errata on Intel regarding the usage of the MONITOR/MWAIT instructions, all having in common that stores to the monitored region might not wake up the CPU. Fix them by forcing the sending of an IPI for the affected models. The Ice Lake issue has been reproduced internally on XenServer hardware, and the fix does seem to prevent it.

xen/riscv: Increase XEN_VIRT_SIZE
Oleksii Kurochko: A randconfig job failed with the following issue: riscv64-linux-gnu-ld: Xen too large for early-boot assumptions The reason is that enabling the UBSAN config increased the size of the Xen binary. Increase XEN_VIRT_SIZE to reserve enough space, allowing both UBSAN and GCOV to be enabled together, with some slack for future growth. Additionally, add checks to verify that XEN_VIRT_START is 1GB-aligned and XEN_VIRT_SIZE is 2MB-aligned to reduce the number of page tables needed for the initial mapping.

CI: Add Arm64/Arm32 MPU build jobs
Michal Orzel: Just like for RISCV and PPC, the earlier we enable the CI build the better.

xen/riscv: implement basic aplic_preinit()
Oleksii Kurochko: Introduce preinitialization stuff for the RISC-V Advanced Platform-Level Interrupt Controller (APLIC) in Xen:- Implementing the APLIC pre-initialization function (`aplic_preinit()`), ensuring that only one APLIC instance is supported in S mode.

xen/riscv: implement software page table walking
Oleksii Kurochko: RISC-V doesn't have hardware feature to ask MMU to translate

radix-tree: don't left-shift negative values
Jan Beulich: Any (signed) integer is okay to pass into radix_tree_int_to_ptr(), yet left shifting negative values is UB.

xen/x86: add CPPC feature flag for AMD processors
Penny Zheng: Add Collaborative Processor Performance Control feature flag for AMD processors. amd-cppc is the AMD CPU performance scaling driver that introduces a new CPU frequency control mechanism on modern AMD APU and CPU series.

x86/MCE-telem: adjust cookie definition
Jan Beulich: struct mctelem_ent is opaque outside of mcetelem.c; the cookie abstraction exists - afaict - just to achieve this opaqueness.

misra: add deviation for MISRA C Rule R11.8
Alessandro Zucchelli: Rule 11.8 states as following: "A cast shall not remove any `const' or `volatile' qualification from the type pointed to by a pointer". Function `__hvm_copy' in `xen/arch/x86/hvm/hvm.c' is a double-use function, where the parameter needs to not be const because it can be set for write or not.

tools/xl: add suspend and resume subcommands
zithro / Cyril Rébert: The xl command doesn't provide suspend/resume, so add them : xl suspend <Domain> xl resume <Domain>

Xen Release Tags

Update QEMU_UPSTREAM_REVISION for 4.4.0-rc4
Ian Jackson

QEMU_UPSTREAM_REVISION update
Ian Jackson

xen: arm: fix build after libelf changes
Ian Campbell: ed65808a8ed4 "libelf: check all pointer accesses" caused: kernel.c: In function 'kernel_elf_load': kernel.c:162:18: error: 'struct elf_binary' has no member named 'dest' make[4]: *** [kernel.o] Error 1 The field is now called dest_base.

gnttab: drop unused GNTCOPY_can_fail
Jan Beulich

libxc: limit cpu values when setting vcpu affinity
Ian Jackson: When support for pinning more than 64 cpus was added, check for cpu out-of-range values was removed.

x86/hvm: avoid p2m lookups for vlapic accesses
Tim Deegan: The LAPIC base address is a known GFN, so we can skip looking up the p2m: we know it should be handled as emulated MMIO.

Config.mk: update QEMU_TAG and QEMU_UPSTREAM_REVISION for 4.3.0-rc1
Ian Jackson

Most Popular This Year

tools/xl: add suspend and resume subcommands
zithro / Cyril Rébert: The xl command doesn't provide suspend/resume, so add them : xl suspend <Domain> xl resume <Domain>

xen/riscv: implement software page table walking
Oleksii Kurochko: RISC-V doesn't have hardware feature to ask MMU to translate

xen/riscv: implement basic aplic_preinit()
Oleksii Kurochko: Introduce preinitialization stuff for the RISC-V Advanced Platform-Level Interrupt Controller (APLIC) in Xen:- Implementing the APLIC pre-initialization function (`aplic_preinit()`), ensuring that only one APLIC instance is supported in S mode.

x86/idle: Implement a new MWAIT IPI-elision algorithm
Andrew Cooper: In order elide IPIs, we must be able to identify whether a target CPU is in MWAIT at the point it is woken up.

misra: add deviation for MISRA C Rule R11.8
Alessandro Zucchelli: Rule 11.8 states as following: "A cast shall not remove any `const' or `volatile' qualification from the type pointed to by a pointer". Function `__hvm_copy' in `xen/arch/x86/hvm/hvm.c' is a double-use function, where the parameter needs to not be const because it can be set for write or not.

radix-tree: don't left-shift negative values
Jan Beulich: Any (signed) integer is okay to pass into radix_tree_int_to_ptr(), yet left shifting negative values is UB.

xen/x86: add CPPC feature flag for AMD processors
Penny Zheng: Add Collaborative Processor Performance Control feature flag for AMD processors. amd-cppc is the AMD CPU performance scaling driver that introduces a new CPU frequency control mechanism on modern AMD APU and CPU series.

drivers/pci: Add minor comment for maximum capability constant
Frediano Ziglio: The comment is similar to extended capabilities in the function below.

CI: Add Arm64/Arm32 MPU build jobs
Michal Orzel: Just like for RISCV and PPC, the earlier we enable the CI build the better.

x86/MCE-telem: adjust cookie definition
Jan Beulich: struct mctelem_ent is opaque outside of mcetelem.c; the cookie abstraction exists - afaict - just to achieve this opaqueness.

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