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author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-05 09:36:29 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-05 09:36:29 +0100 |
commit | 9365f0de4303f82ed4c2db1c39d3de824b249d80 (patch) | |
tree | 2429440aa61c31608557adae2d8fd9228dee7622 /Documentation | |
parent | f36ee841165b2234db8346eb8d5381626e5ab524 (diff) | |
parent | 59b723cd2adbac2a34fc8e12c74ae26ae45bf230 (diff) | |
download | linux-stable-9365f0de4303f82ed4c2db1c39d3de824b249d80.tar.gz linux-stable-9365f0de4303f82ed4c2db1c39d3de824b249d80.tar.bz2 linux-stable-9365f0de4303f82ed4c2db1c39d3de824b249d80.zip |
Merge 6.12-rc6 into char-misc-next
We need the char/misc/iio fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/admin-guide/pm/cpufreq.rst | 20 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.yaml | 24 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/display/mediatek/mediatek,split.yaml | 19 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml | 21 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml | 5 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/sound/davinci-mcasp-audio.yaml | 18 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/sound/rockchip,rk3308-codec.yaml | 4 | ||||
-rw-r--r-- | Documentation/filesystems/caching/cachefiles.rst | 2 | ||||
-rw-r--r-- | Documentation/filesystems/netfs_library.rst | 1 | ||||
-rw-r--r-- | Documentation/iio/ad7380.rst | 13 | ||||
-rw-r--r-- | Documentation/networking/packet_mmap.rst | 5 | ||||
-rw-r--r-- | Documentation/rust/arch-support.rst | 2 | ||||
-rw-r--r-- | Documentation/userspace-api/mseal.rst | 307 | ||||
-rw-r--r-- | Documentation/virt/kvm/api.rst | 16 | ||||
-rw-r--r-- | Documentation/virt/kvm/locking.rst | 2 |
15 files changed, 250 insertions, 209 deletions
diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst index fe1be4ad88cb..a21369eba034 100644 --- a/Documentation/admin-guide/pm/cpufreq.rst +++ b/Documentation/admin-guide/pm/cpufreq.rst @@ -425,8 +425,8 @@ This governor exposes only one tunable: ``rate_limit_us`` Minimum time (in microseconds) that has to pass between two consecutive - runs of governor computations (default: 1000 times the scaling driver's - transition latency). + runs of governor computations (default: 1.5 times the scaling driver's + transition latency or the maximum 2ms). The purpose of this tunable is to reduce the scheduler context overhead of the governor which might be excessive without it. @@ -474,17 +474,17 @@ This governor exposes the following tunables: This is how often the governor's worker routine should run, in microseconds. - Typically, it is set to values of the order of 10000 (10 ms). Its - default value is equal to the value of ``cpuinfo_transition_latency`` - for each policy this governor is attached to (but since the unit here - is greater by 1000, this means that the time represented by - ``sampling_rate`` is 1000 times greater than the transition latency by - default). + Typically, it is set to values of the order of 2000 (2 ms). Its + default value is to add a 50% breathing room + to ``cpuinfo_transition_latency`` on each policy this governor is + attached to. The minimum is typically the length of two scheduler + ticks. If this tunable is per-policy, the following shell command sets the time - represented by it to be 750 times as high as the transition latency:: + represented by it to be 1.5 times as high as the transition latency + (the default):: - # echo `$(($(cat cpuinfo_transition_latency) * 750 / 1000)) > ondemand/sampling_rate + # echo `$(($(cat cpuinfo_transition_latency) * 3 / 2)) > ondemand/sampling_rate ``up_threshold`` If the estimated CPU load is above this value (in percent), the governor diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.yaml b/Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.yaml index 3a82aec9021c..497c0eb4ed0b 100644 --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.yaml +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,dpi.yaml @@ -63,6 +63,16 @@ properties: - const: sleep power-domains: + description: | + The MediaTek DPI module is typically associated with one of the + following multimedia power domains: + POWER_DOMAIN_DISPLAY + POWER_DOMAIN_VDOSYS + POWER_DOMAIN_MM + The specific power domain used varies depending on the SoC design. + + It is recommended to explicitly add the appropriate power domain + property to the DPI node in the device tree. maxItems: 1 port: @@ -79,20 +89,6 @@ required: - clock-names - port -allOf: - - if: - not: - properties: - compatible: - contains: - enum: - - mediatek,mt6795-dpi - - mediatek,mt8173-dpi - - mediatek,mt8186-dpi - then: - properties: - power-domains: false - additionalProperties: false examples: diff --git a/Documentation/devicetree/bindings/display/mediatek/mediatek,split.yaml b/Documentation/devicetree/bindings/display/mediatek/mediatek,split.yaml index e4affc854f3d..4b6ff546757e 100644 --- a/Documentation/devicetree/bindings/display/mediatek/mediatek,split.yaml +++ b/Documentation/devicetree/bindings/display/mediatek/mediatek,split.yaml @@ -38,6 +38,7 @@ properties: description: A phandle and PM domain specifier as defined by bindings of the power controller specified by phandle. See Documentation/devicetree/bindings/power/power-domain.yaml for details. + maxItems: 1 mediatek,gce-client-reg: description: @@ -57,6 +58,9 @@ properties: clocks: items: - description: SPLIT Clock + - description: Used for interfacing with the HDMI RX signal source. + - description: Paired with receiving HDMI RX metadata. + minItems: 1 required: - compatible @@ -72,9 +76,24 @@ allOf: const: mediatek,mt8195-mdp3-split then: + properties: + clocks: + minItems: 3 + required: - mediatek,gce-client-reg + - if: + properties: + compatible: + contains: + const: mediatek,mt8173-disp-split + + then: + properties: + clocks: + maxItems: 1 + additionalProperties: false examples: diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml index bd19abb867d9..0065d6508824 100644 --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml @@ -67,6 +67,10 @@ properties: A 2.5V to 3.3V supply for the external reference voltage. When omitted, the internal 2.5V reference is used. + refin-supply: + description: + A 2.5V to 3.3V supply for external reference voltage, for ad7380-4 only. + aina-supply: description: The common mode voltage supply for the AINA- pin on pseudo-differential @@ -135,6 +139,23 @@ allOf: ainc-supply: false aind-supply: false + # ad7380-4 uses refin-supply as external reference. + # All other chips from ad738x family use refio as optional external reference. + # When refio-supply is omitted, internal reference is used. + - if: + properties: + compatible: + enum: + - adi,ad7380-4 + then: + properties: + refio-supply: false + required: + - refin-supply + else: + properties: + refin-supply: false + examples: - | #include <dt-bindings/interrupt-controller/irq.h> diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml index dcf4fa55fbba..380a9222a51d 100644 --- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml +++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml @@ -154,8 +154,6 @@ allOf: - qcom,sm8550-qmp-gen4x2-pcie-phy - qcom,sm8650-qmp-gen3x2-pcie-phy - qcom,sm8650-qmp-gen4x2-pcie-phy - - qcom,x1e80100-qmp-gen3x2-pcie-phy - - qcom,x1e80100-qmp-gen4x2-pcie-phy then: properties: clocks: @@ -171,6 +169,8 @@ allOf: - qcom,sc8280xp-qmp-gen3x1-pcie-phy - qcom,sc8280xp-qmp-gen3x2-pcie-phy - qcom,sc8280xp-qmp-gen3x4-pcie-phy + - qcom,x1e80100-qmp-gen3x2-pcie-phy + - qcom,x1e80100-qmp-gen4x2-pcie-phy - qcom,x1e80100-qmp-gen4x4-pcie-phy then: properties: @@ -201,6 +201,7 @@ allOf: - qcom,sm8550-qmp-gen4x2-pcie-phy - qcom,sm8650-qmp-gen4x2-pcie-phy - qcom,x1e80100-qmp-gen4x2-pcie-phy + - qcom,x1e80100-qmp-gen4x4-pcie-phy then: properties: resets: diff --git a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.yaml b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.yaml index ab3206ffa4af..beef193aaaeb 100644 --- a/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.yaml +++ b/Documentation/devicetree/bindings/sound/davinci-mcasp-audio.yaml @@ -102,21 +102,21 @@ properties: default: 2 interrupts: - oneOf: - - minItems: 1 - items: - - description: TX interrupt - - description: RX interrupt - - items: - - description: common/combined interrupt + minItems: 1 + maxItems: 2 interrupt-names: oneOf: - - minItems: 1 + - description: TX interrupt + const: tx + - description: RX interrupt + const: rx + - description: TX and RX interrupts items: - const: tx - const: rx - - const: common + - description: Common/combined interrupt + const: common fck_parent: $ref: /schemas/types.yaml#/definitions/string diff --git a/Documentation/devicetree/bindings/sound/rockchip,rk3308-codec.yaml b/Documentation/devicetree/bindings/sound/rockchip,rk3308-codec.yaml index ecf3d7d968c8..2cf229a076f0 100644 --- a/Documentation/devicetree/bindings/sound/rockchip,rk3308-codec.yaml +++ b/Documentation/devicetree/bindings/sound/rockchip,rk3308-codec.yaml @@ -48,6 +48,10 @@ properties: - const: mclk_rx - const: hclk + port: + $ref: audio-graph-port.yaml# + unevaluatedProperties: false + resets: maxItems: 1 diff --git a/Documentation/filesystems/caching/cachefiles.rst b/Documentation/filesystems/caching/cachefiles.rst index e04a27bdbe19..b3ccc782cb3b 100644 --- a/Documentation/filesystems/caching/cachefiles.rst +++ b/Documentation/filesystems/caching/cachefiles.rst @@ -115,7 +115,7 @@ set up cache ready for use. The following script commands are available: This mask can also be set through sysfs, eg:: - echo 5 >/sys/modules/cachefiles/parameters/debug + echo 5 > /sys/module/cachefiles/parameters/debug Starting the Cache diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst index f0d2cb257bb8..73f0bfd7e903 100644 --- a/Documentation/filesystems/netfs_library.rst +++ b/Documentation/filesystems/netfs_library.rst @@ -592,4 +592,3 @@ API Function Reference .. kernel-doc:: include/linux/netfs.h .. kernel-doc:: fs/netfs/buffered_read.c -.. kernel-doc:: fs/netfs/io.c diff --git a/Documentation/iio/ad7380.rst b/Documentation/iio/ad7380.rst index 9c784c1e652e..6f70b49b9ef2 100644 --- a/Documentation/iio/ad7380.rst +++ b/Documentation/iio/ad7380.rst @@ -41,13 +41,22 @@ supports only 1 SDO line. Reference voltage ----------------- -2 possible reference voltage sources are supported: +ad7380-4 +~~~~~~~~ + +ad7380-4 supports only an external reference voltage (2.5V to 3.3V). It must be +declared in the device tree as ``refin-supply``. + +All other devices from ad738x family +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +All other devices from ad738x support 2 possible reference voltage sources: - Internal reference (2.5V) - External reference (2.5V to 3.3V) The source is determined by the device tree. If ``refio-supply`` is present, -then the external reference is used, else the internal reference is used. +then it is used as external reference, else the internal reference is used. Oversampling and resolution boost --------------------------------- diff --git a/Documentation/networking/packet_mmap.rst b/Documentation/networking/packet_mmap.rst index dca15d15feaf..02370786e77b 100644 --- a/Documentation/networking/packet_mmap.rst +++ b/Documentation/networking/packet_mmap.rst @@ -16,7 +16,7 @@ ii) transmit network traffic, or any other that needs raw Howto can be found at: - https://sites.google.com/site/packetmmap/ + https://web.archive.org/web/20220404160947/https://sites.google.com/site/packetmmap/ Please send your comments to - Ulisses Alonso Camaró <uaca@i.hate.spam.alumni.uv.es> @@ -166,7 +166,8 @@ As capture, each frame contains two parts:: /* bind socket to eth0 */ bind(this->socket, (struct sockaddr *)&my_addr, sizeof(struct sockaddr_ll)); - A complete tutorial is available at: https://sites.google.com/site/packetmmap/ + A complete tutorial is available at: + https://web.archive.org/web/20220404160947/https://sites.google.com/site/packetmmap/ By default, the user should put data at:: diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst index 750ff371570a..54be7ddf3e57 100644 --- a/Documentation/rust/arch-support.rst +++ b/Documentation/rust/arch-support.rst @@ -17,7 +17,7 @@ Architecture Level of support Constraints ============= ================ ============================================== ``arm64`` Maintained Little Endian only. ``loongarch`` Maintained \- -``riscv`` Maintained ``riscv64`` only. +``riscv`` Maintained ``riscv64`` and LLVM/Clang only. ``um`` Maintained \- ``x86`` Maintained ``x86_64`` only. ============= ================ ============================================== diff --git a/Documentation/userspace-api/mseal.rst b/Documentation/userspace-api/mseal.rst index 4132eec995a3..41102f74c5e2 100644 --- a/Documentation/userspace-api/mseal.rst +++ b/Documentation/userspace-api/mseal.rst @@ -23,177 +23,166 @@ applications can additionally seal security critical data at runtime. A similar feature already exists in the XNU kernel with the VM_FLAGS_PERMANENT flag [1] and on OpenBSD with the mimmutable syscall [2]. -User API -======== -mseal() ------------ -The mseal() syscall has the following signature: - -``int mseal(void addr, size_t len, unsigned long flags)`` - -**addr/len**: virtual memory address range. - -The address range set by ``addr``/``len`` must meet: - - The start address must be in an allocated VMA. - - The start address must be page aligned. - - The end address (``addr`` + ``len``) must be in an allocated VMA. - - no gap (unallocated memory) between start and end address. - -The ``len`` will be paged aligned implicitly by the kernel. - -**flags**: reserved for future use. - -**return values**: - -- ``0``: Success. - -- ``-EINVAL``: - - Invalid input ``flags``. - - The start address (``addr``) is not page aligned. - - Address range (``addr`` + ``len``) overflow. - -- ``-ENOMEM``: - - The start address (``addr``) is not allocated. - - The end address (``addr`` + ``len``) is not allocated. - - A gap (unallocated memory) between start and end address. - -- ``-EPERM``: - - sealing is supported only on 64-bit CPUs, 32-bit is not supported. - -- For above error cases, users can expect the given memory range is - unmodified, i.e. no partial update. - -- There might be other internal errors/cases not listed here, e.g. - error during merging/splitting VMAs, or the process reaching the max - number of supported VMAs. In those cases, partial updates to the given - memory range could happen. However, those cases should be rare. - -**Blocked operations after sealing**: - Unmapping, moving to another location, and shrinking the size, - via munmap() and mremap(), can leave an empty space, therefore - can be replaced with a VMA with a new set of attributes. - - Moving or expanding a different VMA into the current location, - via mremap(). - - Modifying a VMA via mmap(MAP_FIXED). - - Size expansion, via mremap(), does not appear to pose any - specific risks to sealed VMAs. It is included anyway because - the use case is unclear. In any case, users can rely on - merging to expand a sealed VMA. - - mprotect() and pkey_mprotect(). - - Some destructive madvice() behaviors (e.g. MADV_DONTNEED) - for anonymous memory, when users don't have write permission to the - memory. Those behaviors can alter region contents by discarding pages, - effectively a memset(0) for anonymous memory. - - Kernel will return -EPERM for blocked operations. - - For blocked operations, one can expect the given address is unmodified, - i.e. no partial update. Note, this is different from existing mm - system call behaviors, where partial updates are made till an error is - found and returned to userspace. To give an example: - - Assume following code sequence: - - - ptr = mmap(null, 8192, PROT_NONE); - - munmap(ptr + 4096, 4096); - - ret1 = mprotect(ptr, 8192, PROT_READ); - - mseal(ptr, 4096); - - ret2 = mprotect(ptr, 8192, PROT_NONE); - - ret1 will be -ENOMEM, the page from ptr is updated to PROT_READ. - - ret2 will be -EPERM, the page remains to be PROT_READ. - -**Note**: - -- mseal() only works on 64-bit CPUs, not 32-bit CPU. - -- users can call mseal() multiple times, mseal() on an already sealed memory - is a no-action (not error). - -- munseal() is not supported. - -Use cases: -========== +SYSCALL +======= +mseal syscall signature +----------------------- + ``int mseal(void \* addr, size_t len, unsigned long flags)`` + + **addr**/**len**: virtual memory address range. + The address range set by **addr**/**len** must meet: + - The start address must be in an allocated VMA. + - The start address must be page aligned. + - The end address (**addr** + **len**) must be in an allocated VMA. + - no gap (unallocated memory) between start and end address. + + The ``len`` will be paged aligned implicitly by the kernel. + + **flags**: reserved for future use. + + **Return values**: + - **0**: Success. + - **-EINVAL**: + * Invalid input ``flags``. + * The start address (``addr``) is not page aligned. + * Address range (``addr`` + ``len``) overflow. + - **-ENOMEM**: + * The start address (``addr``) is not allocated. + * The end address (``addr`` + ``len``) is not allocated. + * A gap (unallocated memory) between start and end address. + - **-EPERM**: + * sealing is supported only on 64-bit CPUs, 32-bit is not supported. + + **Note about error return**: + - For above error cases, users can expect the given memory range is + unmodified, i.e. no partial update. + - There might be other internal errors/cases not listed here, e.g. + error during merging/splitting VMAs, or the process reaching the maximum + number of supported VMAs. In those cases, partial updates to the given + memory range could happen. However, those cases should be rare. + + **Architecture support**: + mseal only works on 64-bit CPUs, not 32-bit CPUs. + + **Idempotent**: + users can call mseal multiple times. mseal on an already sealed memory + is a no-action (not error). + + **no munseal** + Once mapping is sealed, it can't be unsealed. The kernel should never + have munseal, this is consistent with other sealing feature, e.g. + F_SEAL_SEAL for file. + +Blocked mm syscall for sealed mapping +------------------------------------- + It might be important to note: **once the mapping is sealed, it will + stay in the process's memory until the process terminates**. + + Example:: + + *ptr = mmap(0, 4096, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + rc = mseal(ptr, 4096, 0); + /* munmap will fail */ + rc = munmap(ptr, 4096); + assert(rc < 0); + + Blocked mm syscall: + - munmap + - mmap + - mremap + - mprotect and pkey_mprotect + - some destructive madvise behaviors: MADV_DONTNEED, MADV_FREE, + MADV_DONTNEED_LOCKED, MADV_FREE, MADV_DONTFORK, MADV_WIPEONFORK + + The first set of syscalls to block is munmap, mremap, mmap. They can + either leave an empty space in the address space, therefore allowing + replacement with a new mapping with new set of attributes, or can + overwrite the existing mapping with another mapping. + + mprotect and pkey_mprotect are blocked because they changes the + protection bits (RWX) of the mapping. + + Certain destructive madvise behaviors, specifically MADV_DONTNEED, + MADV_FREE, MADV_DONTNEED_LOCKED, and MADV_WIPEONFORK, can introduce + risks when applied to anonymous memory by threads lacking write + permissions. Consequently, these operations are prohibited under such + conditions. The aforementioned behaviors have the potential to modify + region contents by discarding pages, effectively performing a memset(0) + operation on the anonymous memory. + + Kernel will return -EPERM for blocked syscalls. + + When blocked syscall return -EPERM due to sealing, the memory regions may + or may not be changed, depends on the syscall being blocked: + + - munmap: munmap is atomic. If one of VMAs in the given range is + sealed, none of VMAs are updated. + - mprotect, pkey_mprotect, madvise: partial update might happen, e.g. + when mprotect over multiple VMAs, mprotect might update the beginning + VMAs before reaching the sealed VMA and return -EPERM. + - mmap and mremap: undefined behavior. + +Use cases +========= - glibc: The dynamic linker, during loading ELF executables, can apply sealing to - non-writable memory segments. - -- Chrome browser: protect some security sensitive data-structures. + mapping segments. -Notes on which memory to seal: -============================== +- Chrome browser: protect some security sensitive data structures. -It might be important to note that sealing changes the lifetime of a mapping, -i.e. the sealed mapping won’t be unmapped till the process terminates or the -exec system call is invoked. Applications can apply sealing to any virtual -memory region from userspace, but it is crucial to thoroughly analyze the -mapping's lifetime prior to apply the sealing. +When not to use mseal +===================== +Applications can apply sealing to any virtual memory region from userspace, +but it is *crucial to thoroughly analyze the mapping's lifetime* prior to +apply the sealing. This is because the sealed mapping *won’t be unmapped* +until the process terminates or the exec system call is invoked. For example: + - aio/shm + aio/shm can call mmap and munmap on behalf of userspace, e.g. + ksys_shmdt() in shm.c. The lifetimes of those mapping are not tied to + the lifetime of the process. If those memories are sealed from userspace, + then munmap will fail, causing leaks in VMA address space during the + lifetime of the process. + + - ptr allocated by malloc (heap) + Don't use mseal on the memory ptr return from malloc(). + malloc() is implemented by allocator, e.g. by glibc. Heap manager might + allocate a ptr from brk or mapping created by mmap. + If an app calls mseal on a ptr returned from malloc(), this can affect + the heap manager's ability to manage the mappings; the outcome is + non-deterministic. + + Example:: + + ptr = malloc(size); + /* don't call mseal on ptr return from malloc. */ + mseal(ptr, size); + /* free will success, allocator can't shrink heap lower than ptr */ + free(ptr); + +mseal doesn't block +=================== +In a nutshell, mseal blocks certain mm syscall from modifying some of VMA's +attributes, such as protection bits (RWX). Sealed mappings doesn't mean the +memory is immutable. -- aio/shm - - aio/shm can call mmap()/munmap() on behalf of userspace, e.g. ksys_shmdt() in - shm.c. The lifetime of those mapping are not tied to the lifetime of the - process. If those memories are sealed from userspace, then munmap() will fail, - causing leaks in VMA address space during the lifetime of the process. - -- Brk (heap) - - Currently, userspace applications can seal parts of the heap by calling - malloc() and mseal(). - let's assume following calls from user space: - - - ptr = malloc(size); - - mprotect(ptr, size, RO); - - mseal(ptr, size); - - free(ptr); - - Technically, before mseal() is added, the user can change the protection of - the heap by calling mprotect(RO). As long as the user changes the protection - back to RW before free(), the memory range can be reused. - - Adding mseal() into the picture, however, the heap is then sealed partially, - the user can still free it, but the memory remains to be RO. If the address - is re-used by the heap manager for another malloc, the process might crash - soon after. Therefore, it is important not to apply sealing to any memory - that might get recycled. - - Furthermore, even if the application never calls the free() for the ptr, - the heap manager may invoke the brk system call to shrink the size of the - heap. In the kernel, the brk-shrink will call munmap(). Consequently, - depending on the location of the ptr, the outcome of brk-shrink is - nondeterministic. - - -Additional notes: -================= As Jann Horn pointed out in [3], there are still a few ways to write -to RO memory, which is, in a way, by design. Those cases are not covered -by mseal(). If applications want to block such cases, sandbox tools (such as -seccomp, LSM, etc) might be considered. +to RO memory, which is, in a way, by design. And those could be blocked +by different security measures. Those cases are: -- Write to read-only memory through /proc/self/mem interface. -- Write to read-only memory through ptrace (such as PTRACE_POKETEXT). -- userfaultfd. + - Write to read-only memory through /proc/self/mem interface (FOLL_FORCE). + - Write to read-only memory through ptrace (such as PTRACE_POKETEXT). + - userfaultfd. The idea that inspired this patch comes from Stephen Röttger’s work in V8 CFI [4]. Chrome browser in ChromeOS will be the first user of this API. -Reference: -========== -[1] https://github.com/apple-oss-distributions/xnu/blob/1031c584a5e37aff177559b9f69dbd3c8c3fd30a/osfmk/mach/vm_statistics.h#L274 - -[2] https://man.openbsd.org/mimmutable.2 - -[3] https://lore.kernel.org/lkml/CAG48ez3ShUYey+ZAFsU2i1RpQn0a5eOs2hzQ426FkcgnfUGLvA@mail.gmail.com - -[4] https://docs.google.com/document/d/1O2jwK4dxI3nRcOJuPYkonhTkNQfbmwdvxQMyXgeaRHo/edit#heading=h.bvaojj9fu6hc +Reference +========= +- [1] https://github.com/apple-oss-distributions/xnu/blob/1031c584a5e37aff177559b9f69dbd3c8c3fd30a/osfmk/mach/vm_statistics.h#L274 +- [2] https://man.openbsd.org/mimmutable.2 +- [3] https://lore.kernel.org/lkml/CAG48ez3ShUYey+ZAFsU2i1RpQn0a5eOs2hzQ426FkcgnfUGLvA@mail.gmail.com +- [4] https://docs.google.com/document/d/1O2jwK4dxI3nRcOJuPYkonhTkNQfbmwdvxQMyXgeaRHo/edit#heading=h.bvaojj9fu6hc diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index e32471977d0a..edc070c6e19b 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -8098,13 +8098,15 @@ KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is disabled. -KVM_X86_QUIRK_SLOT_ZAP_ALL By default, KVM invalidates all SPTEs in - fast way for memslot deletion when VM type - is KVM_X86_DEFAULT_VM. - When this quirk is disabled or when VM type - is other than KVM_X86_DEFAULT_VM, KVM zaps - only leaf SPTEs that are within the range of - the memslot being deleted. +KVM_X86_QUIRK_SLOT_ZAP_ALL By default, for KVM_X86_DEFAULT_VM VMs, KVM + invalidates all SPTEs in all memslots and + address spaces when a memslot is deleted or + moved. When this quirk is disabled (or the + VM type isn't KVM_X86_DEFAULT_VM), KVM only + ensures the backing memory of the deleted + or moved memslot isn't reachable, i.e KVM + _may_ invalidate only SPTEs related to the + memslot. =================================== ============================================ 7.32 KVM_CAP_MAX_VCPU_ID diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst index 20a9a37d1cdd..1bedd56e2fe3 100644 --- a/Documentation/virt/kvm/locking.rst +++ b/Documentation/virt/kvm/locking.rst @@ -136,7 +136,7 @@ For direct sp, we can easily avoid it since the spte of direct sp is fixed to gfn. For indirect sp, we disabled fast page fault for simplicity. A solution for indirect sp could be to pin the gfn, for example via -kvm_vcpu_gfn_to_pfn_atomic, before the cmpxchg. After the pinning: +gfn_to_pfn_memslot_atomic, before the cmpxchg. After the pinning: - We have held the refcount of pfn; that means the pfn can not be freed and be reused for another gfn. |