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[PATCH v3 0/3] Address page fault in ima_restore_measurement_list()

by Harshit Mogalapalli

On x86_64: When the second-stage kernel is booted via kexec with a limiting command line such as "mem=<size>" we observe a pafe fault that happens. BUG: unable to handle page fault for address: ffff97793ff47000 RIP: ima_restore_measurement_list+0xdc/0x45a #PF: error_code(0x0000) – not-present page This happens on x86_64 only, as this is already fixed in aarch64 in commit: cbf9c4b9617b ("of: check previous kernel's ima-kexec-buffer against memory bounds") V1: https://lore.kernel.org/all/20251112193005.3772542-1-harshit.m.mogalapalli@… V1 attempted to do a similar sanity check in x86_64. Borislav suggested to add a generic helper ima_validate_range() which could then be used for both OF based and x86_64. Testing information: -------------------- On x86_64: With latest 6.19-rc2 based, we could reproduce the issue, and patched kernel works fine. (with mem=8G on a 16G memory machine) Thanks to Yifei for finding enabling IMA_KEXEC is the cause. Thanks for the reviews on V1. V1 -> V2: - Patch 1: Add a generic helper "ima_validate_range()" - Patch 2: Use this new helper in drivers/of/kexec.c -> No functional change. - Patch 3: Fix the page fault by doing sanity check with "ima_validate_range()" V2: https://lore.kernel.org/all/20251229081523.622515-1-harshit.m.mogalapalli@o… V2 -> V3: Update subject of Patch 1 to more appropriate one (Suggested by Mimi Zohar) Thanks, Harshit Harshit Mogalapalli (3): ima: verify the previous kernel's IMA buffer lies in addressable RAM of/kexec: refactor ima_get_kexec_buffer() to use ima_validate_range() x86/kexec: Add a sanity check on previous kernel's ima kexec buffer arch/x86/kernel/setup.c | 6 +++++ drivers/of/kexec.c | 15 +++---------- include/linux/ima.h | 1 + security/integrity/ima/ima_kexec.c | 35 ++++++++++++++++++++++++++++++ 4 files changed, 45 insertions(+), 12 deletions(-) -- 2.50.1

5 days, 19 hours

[PATCH 1/2] writeback: fix 100% CPU usage when dirtytime_expire_interval is 0

by Laveesh Bansal

When vm.dirtytime_expire_seconds is set to 0, wakeup_dirtytime_writeback() schedules delayed work with a delay of 0, causing immediate execution. The function then reschedules itself with 0 delay again, creating an infinite busy loop that causes 100% kworker CPU usage. Fix by: - Only scheduling delayed work in wakeup_dirtytime_writeback() when dirtytime_expire_interval is non-zero - Cancelling the delayed work in dirtytime_interval_handler() when the interval is set to 0 - Adding a guard in start_dirtytime_writeback() for defensive coding Tested by booting kernel in QEMU with virtme-ng: - Before fix: kworker CPU spikes to ~73% - After fix: CPU remains at normal levels - Setting interval back to non-zero correctly resumes writeback Fixes: a2f4870697a5 ("fs: make sure the timestamps for lazytime inodes eventually get written") Cc: stable(a)vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220227 Signed-off-by: Laveesh Bansal <laveeshb(a)laveeshbansal.com> --- fs/fs-writeback.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 6800886c4d10..cd21c74cd0e5 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2492,7 +2492,8 @@ static void wakeup_dirtytime_writeback(struct work_struct *w) wb_wakeup(wb); } rcu_read_unlock(); - schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); + if (dirtytime_expire_interval) + schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); } static int dirtytime_interval_handler(const struct ctl_table *table, int write, @@ -2501,8 +2502,12 @@ static int dirtytime_interval_handler(const struct ctl_table *table, int write, int ret; ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); - if (ret == 0 && write) - mod_delayed_work(system_percpu_wq, &dirtytime_work, 0); + if (ret == 0 && write) { + if (dirtytime_expire_interval) + mod_delayed_work(system_percpu_wq, &dirtytime_work, 0); + else + cancel_delayed_work_sync(&dirtytime_work); + } return ret; } @@ -2519,7 +2524,8 @@ static const struct ctl_table vm_fs_writeback_table[] = { static int __init start_dirtytime_writeback(void) { - schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); + if (dirtytime_expire_interval) + schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); register_sysctl_init("vm", vm_fs_writeback_table); return 0; } -- 2.43.0

5 days, 19 hours

[PATCH 1/2] writeback: fix 100% CPU usage when dirtytime_expire_interval is 0

by Laveesh Bansal

From: Laveesh Bansal <laveeshbansal(a)gmail.com> When vm.dirtytime_expire_seconds is set to 0, wakeup_dirtytime_writeback() schedules delayed work with a delay of 0, causing immediate execution. The function then reschedules itself with 0 delay again, creating an infinite busy loop that causes 100% kworker CPU usage. Fix by: - Only scheduling delayed work in wakeup_dirtytime_writeback() when dirtytime_expire_interval is non-zero - Cancelling the delayed work in dirtytime_interval_handler() when the interval is set to 0 - Adding a guard in start_dirtytime_writeback() for defensive coding Tested by booting kernel in QEMU with virtme-ng: - Before fix: kworker CPU spikes to ~73% - After fix: CPU remains at normal levels - Setting interval back to non-zero correctly resumes writeback Fixes: a2f4870697a5 ("fs: make sure the timestamps for lazytime inodes eventually get written") Cc: stable(a)vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220227 Signed-off-by: Laveesh Bansal <laveeshbansal(a)gmail.com> --- fs/fs-writeback.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 6800886c4d10..cd21c74cd0e5 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2492,7 +2492,8 @@ static void wakeup_dirtytime_writeback(struct work_struct *w) wb_wakeup(wb); } rcu_read_unlock(); - schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); + if (dirtytime_expire_interval) + schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); } static int dirtytime_interval_handler(const struct ctl_table *table, int write, @@ -2501,8 +2502,12 @@ static int dirtytime_interval_handler(const struct ctl_table *table, int write, int ret; ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); - if (ret == 0 && write) - mod_delayed_work(system_percpu_wq, &dirtytime_work, 0); + if (ret == 0 && write) { + if (dirtytime_expire_interval) + mod_delayed_work(system_percpu_wq, &dirtytime_work, 0); + else + cancel_delayed_work_sync(&dirtytime_work); + } return ret; } @@ -2519,7 +2524,8 @@ static const struct ctl_table vm_fs_writeback_table[] = { static int __init start_dirtytime_writeback(void) { - schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); + if (dirtytime_expire_interval) + schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); register_sysctl_init("vm", vm_fs_writeback_table); return 0; } -- 2.43.0

5 days, 19 hours

Re: NRF 2026 Retail's Big Show more information

by Amy Giles

Hi, I wanted to see if you had time to review the email I sent earlier. Should you need any other details, don't hesitate to reach out. Best Amy Giles Please reply with REMOVE if you don't wish to receive further emails -----Original Message----- Hi, Hope you're having a great day! Are you looking for leads from NRF 2026 Retail's Big Show? Attendees count: 30,000 Leads Data Fields: Company Name, Web URL, Contact Name, Title, Direct Email, Phone Number, Mailing Address, Industry, Employee Size, Annual Sales. If you're interested in these leads, I'd be glad to share the pricing. Let me know! Thanks for the quick reply. I'm excited to get your thoughts. Best Amy Giles Demand Generation Manager Zoom Connect, Inc Please reply with REMOVE if you don't wish to receive further emails

5 days, 19 hours

RE: CES 2026: Audience Breakdown & Leads

by Jessica Garcia

Hi , Just touching base to see if you're available to discuss this further. If you have any uncertainties, I'm happy to help. Regards Jessica Marketing Manager Campaign Data Leads., Please reply with REMOVE if you don't wish to receive further emails -----Original Message----- From: Jessica Garcia Subject: CES 2026: Audience Breakdown & Leads Hi , Trust you're in good spirits. Is the idea of buying the CES 2026 attendees' details for your marketing efforts something you'd like to explore? Expo Name: Consumer Electronics Show 2026 Total Number of records: 40,000 records List includes: Company Name, Contact Name, Job Title, Mailing Address, Phone, Emails, etc. Best chance to connect with participants Feel free to contact me if you are interested in acquiring this list so that I can share pricing information with you Hoping for your prompt feedback. Regards Jessica Marketing Manager Campaign Data Leads., Please reply with REMOVE if you don't wish to receive further emails

5 days, 22 hours

[PATCH 2/5] ARM: dts: microchip: sama7d65: fix size-cells property for i2c3

by nicolas.ferre＠microchip.com

From: Nicolas Ferre <nicolas.ferre(a)microchip.com> Fix the #size-cells property for i2c3 node and remove the dtbs_check error telling that "#size-cells: 0 was expected" from schema atmel,at91sam-i2c.yaml and i2c-controller.yaml. Fixes: b51e4aea3ecf ("ARM: dts: microchip: sama7d65: Add FLEXCOMs to sama7d65 SoC") Cc: <stable(a)vger.kernel.org> # 6.16+ Signed-off-by: Nicolas Ferre <nicolas.ferre(a)microchip.com> --- arch/arm/boot/dts/microchip/sama7d65.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/boot/dts/microchip/sama7d65.dtsi b/arch/arm/boot/dts/microchip/sama7d65.dtsi index 5f3a7b178aa7..868045c650a7 100644 --- a/arch/arm/boot/dts/microchip/sama7d65.dtsi +++ b/arch/arm/boot/dts/microchip/sama7d65.dtsi @@ -527,7 +527,7 @@ i2c3: i2c@600 { interrupts = <GIC_SPI 37 IRQ_TYPE_LEVEL_HIGH>; clocks = <&pmc PMC_TYPE_PERIPHERAL 37>; #address-cells = <1>; - #size-cells = <1>; + #size-cells = <0>; dmas = <&dma0 AT91_XDMAC_DT_PERID(12)>, <&dma0 AT91_XDMAC_DT_PERID(11)>; dma-names = "tx", "rx"; -- 2.43.0

5 days, 22 hours

[PATCH 1/5] ARM: dts: microchip: sama7d65: fix the ranges property for flx9

by nicolas.ferre＠microchip.com

From: Hari Prasath Gujulan Elango <hari.prasathge(a)microchip.com> Update the ranges property for the flexcom9 as per the datasheet and align with the reg property. Fixes: b51e4aea3ecf ("ARM: dts: microchip: sama7d65: Add FLEXCOMs to sama7d65 SoC") Cc: <stable(a)vger.kernel.org> # 6.16+ Signed-off-by: Hari Prasath Gujulan Elango <hari.prasathge(a)microchip.com> Signed-off-by: Nicolas Ferre <nicolas.ferre(a)microchip.com> --- Note: Hari's email address will bounce. Change to whichever suits you. arch/arm/boot/dts/microchip/sama7d65.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/boot/dts/microchip/sama7d65.dtsi b/arch/arm/boot/dts/microchip/sama7d65.dtsi index cd2cf9a6f40b..5f3a7b178aa7 100644 --- a/arch/arm/boot/dts/microchip/sama7d65.dtsi +++ b/arch/arm/boot/dts/microchip/sama7d65.dtsi @@ -676,7 +676,7 @@ i2c8: i2c@600 { flx9: flexcom@e2820000 { compatible = "microchip,sama7d65-flexcom", "atmel,sama5d2-flexcom"; reg = <0xe2820000 0x200>; - ranges = <0x0 0xe281c000 0x800>; + ranges = <0x0 0xe2820000 0x800>; clocks = <&pmc PMC_TYPE_PERIPHERAL 43>; #address-cells = <1>; #size-cells = <1>; -- 2.43.0

5 days, 22 hours

[PATCH v5 3/3] KVM: x86: Add x2APIC "features" to control EOI broadcast suppression

by Khushit Shah

Add two flags for KVM_CAP_X2APIC_API to allow userspace to control support for Suppress EOI Broadcasts, which KVM completely mishandles. When x2APIC support was first added, KVM incorrectly advertised and "enabled" Suppress EOI Broadcast, without fully supporting the I/O APIC side of the equation, i.e. without adding directed EOI to KVM's in-kernel I/O APIC. That flaw was carried over to split IRQCHIP support, i.e. KVM advertised support for Suppress EOI Broadcasts irrespective of whether or not the userspace I/O APIC implementation supported directed EOIs. Even worse, KVM didn't actually suppress EOI broadcasts, i.e. userspace VMMs without support for directed EOI came to rely on the "spurious" broadcasts. KVM "fixed" the in-kernel I/O APIC implementation by completely disabling support for Suppress EOI Broadcasts in commit 0bcc3fb95b97 ("KVM: lapic: stop advertising DIRECTED_EOI when in-kernel IOAPIC is in use"), but didn't do anything to remedy userspace I/O APIC implementations. KVM's bogus handling of Suppress EOI Broadcast is problematic when the guest relies on interrupts being masked in the I/O APIC until well after the initial local APIC EOI. E.g. Windows with Credential Guard enabled handles interrupts in the following order: 1. Interrupt for L2 arrives. 2. L1 APIC EOIs the interrupt. 3. L1 resumes L2 and injects the interrupt. 4. L2 EOIs after servicing. 5. L1 performs the I/O APIC EOI. Because KVM EOIs the I/O APIC at step #2, the guest can get an interrupt storm, e.g. if the IRQ line is still asserted and userspace reacts to the EOI by re-injecting the IRQ, because the guest doesn't de-assert the line until step #4, and doesn't expect the interrupt to be re-enabled until step #5. Unfortunately, simply "fixing" the bug isn't an option, as KVM has no way of knowing if the userspace I/O APIC supports directed EOIs, i.e. suppressing EOI broadcasts would result in interrupts being stuck masked in the userspace I/O APIC due to step #5 being ignored by userspace. And fully disabling support for Suppress EOI Broadcast is also undesirable, as picking up the fix would require a guest reboot, *and* more importantly would change the virtual CPU model exposed to the guest without any buy-in from userspace. Add KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST flags to allow userspace to explicitly enable or disable support for Suppress EOI Broadcasts. This gives userspace control over the virtual CPU model exposed to the guest, as KVM should never have enabled support for Suppress EOI Broadcast without userspace opt-in. Not setting either flag will result in legacy quirky behavior for backward compatibility. When KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST is set and using in-kernel IRQCHIP mode, KVM will use I/O APIC version 0x20, which includes support for the EOI Register. Note, Suppress EOI Broadcasts is defined only in Intel's SDM, not in AMD's APM. But the bit is writable on some AMD CPUs, e.g. Turin, and KVM's ABI is to support Directed EOI (KVM's name) irrespective of guest CPU vendor. Fixes: 7543a635aa09 ("KVM: x86: Add KVM exit for IOAPIC EOIs") Closes: https://lore.kernel.org/kvm/7D497EF1-607D-4D37-98E7-DAF95F099342@nutanix.com Cc: stable(a)vger.kernel.org Suggested-by: David Woodhouse <dwmw2(a)infradead.org> Co-developed-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Khushit Shah <khushit.shah(a)nutanix.com> --- Documentation/virt/kvm/api.rst | 28 +++++++++++++-- arch/x86/include/asm/kvm_host.h | 7 ++++ arch/x86/include/uapi/asm/kvm.h | 6 ++-- arch/x86/kvm/lapic.c | 64 ++++++++++++++++++++++----------- arch/x86/kvm/x86.c | 15 ++++++-- 5 files changed, 93 insertions(+), 27 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 57061fa29e6a..ad15ca519afc 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7800,8 +7800,10 @@ Will return -EBUSY if a VCPU has already been created. Valid feature flags in args[0] are:: - #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) - #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) + #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) + #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) + #define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST (1ULL << 2) + #define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST (1ULL << 3) Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, @@ -7814,6 +7816,28 @@ as a broadcast even in x2APIC mode in order to support physical x2APIC without interrupt remapping. This is undesirable in logical mode, where 0xff represents CPUs 0-7 in cluster 0. +Setting KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST instructs KVM to enable +Suppress EOI Broadcasts. KVM will advertise support for Suppress EOI +Broadcast to the guest and suppress LAPIC EOI broadcasts when the guest +sets the Suppress EOI Broadcast bit in the SPIV register. When using +in-kernel IRQCHIP mode, enabling this capability will cause KVM to use +I/O APIC version 0x20, which includes support for the EOI Register for +directed EOI. + +Setting KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST disables support for +Suppress EOI Broadcasts entirely, i.e. instructs KVM to NOT advertise +support to the guest. + +Modern VMMs should either enable KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST +or KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST. If not, legacy quirky +behavior will be used by KVM: in split IRQCHIP mode, KVM will advertise +support for Suppress EOI Broadcasts but not actually suppress EOI +broadcasts; for in-kernel IRQCHIP mode, KVM will not advertise support for +Suppress EOI Broadcasts. + +Setting both KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and +KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST will fail with an EINVAL error. + 7.8 KVM_CAP_S390_USER_INSTR0 ---------------------------- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 48598d017d6f..4a6d94dc7a2a 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1229,6 +1229,12 @@ enum kvm_irqchip_mode { KVM_IRQCHIP_SPLIT, /* created with KVM_CAP_SPLIT_IRQCHIP */ }; +enum kvm_suppress_eoi_broadcast_mode { + KVM_SUPPRESS_EOI_BROADCAST_QUIRKED, /* Legacy behavior */ + KVM_SUPPRESS_EOI_BROADCAST_ENABLED, /* Enable Suppress EOI broadcast */ + KVM_SUPPRESS_EOI_BROADCAST_DISABLED /* Disable Suppress EOI broadcast */ +}; + struct kvm_x86_msr_filter { u8 count; bool default_allow:1; @@ -1480,6 +1486,7 @@ struct kvm_arch { bool x2apic_format; bool x2apic_broadcast_quirk_disabled; + enum kvm_suppress_eoi_broadcast_mode suppress_eoi_broadcast_mode; bool has_mapped_host_mmio; bool guest_can_read_msr_platform_info; diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index d420c9c066d4..d30241429fa8 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -913,8 +913,10 @@ struct kvm_sev_snp_launch_finish { __u64 pad1[4]; }; -#define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) -#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) +#define KVM_X2APIC_API_USE_32BIT_IDS (_BITULL(0)) +#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (_BITULL(1)) +#define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST (_BITULL(2)) +#define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST (_BITULL(3)) struct kvm_hyperv_eventfd { __u32 conn_id; diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 2c24fd8d815f..36a5af218802 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -107,21 +107,31 @@ bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector) bool kvm_lapic_advertise_suppress_eoi_broadcast(struct kvm *kvm) { - /* - * The default in-kernel I/O APIC emulates the 82093AA and does not - * implement an EOI register. Some guests (e.g. Windows with the - * Hyper-V role enabled) disable LAPIC EOI broadcast without checking - * the I/O APIC version, which can cause level-triggered interrupts to - * never be EOI'd. - * - * To avoid this, KVM must not advertise Suppress EOI Broadcast support - * when using the default in-kernel I/O APIC. - * - * Historically, in split IRQCHIP mode, KVM always advertised Suppress - * EOI Broadcast support but did not actually suppress EOIs, resulting - * in quirky behavior. - */ - return !ioapic_in_kernel(kvm); + switch (kvm->arch.suppress_eoi_broadcast_mode) { + case KVM_SUPPRESS_EOI_BROADCAST_ENABLED: + return true; + case KVM_SUPPRESS_EOI_BROADCAST_DISABLED: + return false; + case KVM_SUPPRESS_EOI_BROADCAST_QUIRKED: + /* + * The default in-kernel I/O APIC emulates the 82093AA and does not + * implement an EOI register. Some guests (e.g. Windows with the + * Hyper-V role enabled) disable LAPIC EOI broadcast without + * checking the I/O APIC version, which can cause level-triggered + * interrupts to never be EOI'd. + * + * To avoid this, KVM must not advertise Suppress EOI Broadcast + * support when using the default in-kernel I/O APIC. + * + * Historically, in split IRQCHIP mode, KVM always advertised + * Suppress EOI Broadcast support but did not actually suppress + * EOIs, resulting in quirky behavior. + */ + return !ioapic_in_kernel(kvm); + default: + WARN_ON_ONCE(1); + return false; + } } bool kvm_lapic_respect_suppress_eoi_broadcast(struct kvm *kvm) @@ -129,13 +139,25 @@ bool kvm_lapic_respect_suppress_eoi_broadcast(struct kvm *kvm) /* * Returns true if KVM should honor the guest's request to suppress EOI * broadcasts, i.e. actually implement Suppress EOI Broadcast. - * - * Historically, in split IRQCHIP mode, KVM ignored the suppress EOI - * broadcast bit set by the guest and broadcasts EOIs to the userspace - * I/O APIC. For In-kernel I/O APIC, the support itself is not - * advertised, but if bit was set by the guest, it was respected. */ - return ioapic_in_kernel(kvm); + switch (kvm->arch.suppress_eoi_broadcast_mode) { + case KVM_SUPPRESS_EOI_BROADCAST_ENABLED: + return true; + case KVM_SUPPRESS_EOI_BROADCAST_DISABLED: + return false; + case KVM_SUPPRESS_EOI_BROADCAST_QUIRKED: + /* + * Historically, in split IRQCHIP mode, KVM ignored the suppress + * EOI broadcast bit set by the guest and broadcasts EOIs to the + * userspace I/O APIC. For In-kernel I/O APIC, the support itself + * is not advertised, but if bit was set by the guest, it was + * respected. + */ + return ioapic_in_kernel(kvm); + default: + WARN_ON_ONCE(1); + return false; + } } __read_mostly DEFINE_STATIC_KEY_FALSE(kvm_has_noapic_vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c9c2aa6f4705..5d56b0384dcc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -121,8 +121,10 @@ static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE); #define KVM_CAP_PMU_VALID_MASK KVM_PMU_CAP_DISABLE -#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \ - KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK) +#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \ + KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK | \ + KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST | \ + KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST) static void update_cr8_intercept(struct kvm_vcpu *vcpu); static void process_nmi(struct kvm_vcpu *vcpu); @@ -6778,11 +6780,20 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->args[0] & ~KVM_X2APIC_API_VALID_FLAGS) break; + if ((cap->args[0] & KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST) && + (cap->args[0] & KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST)) + break; + if (cap->args[0] & KVM_X2APIC_API_USE_32BIT_IDS) kvm->arch.x2apic_format = true; if (cap->args[0] & KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK) kvm->arch.x2apic_broadcast_quirk_disabled = true; + if (cap->args[0] & KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST) + kvm->arch.suppress_eoi_broadcast_mode = KVM_SUPPRESS_EOI_BROADCAST_ENABLED; + if (cap->args[0] & KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST) + kvm->arch.suppress_eoi_broadcast_mode = KVM_SUPPRESS_EOI_BROADCAST_DISABLED; + r = 0; break; case KVM_CAP_X86_DISABLE_EXITS: -- 2.39.3

5 days, 22 hours

[5.10] regression: virtual consoles 2-12 unusable

by Ben Hutchings

Hello stable maintainers, Several Debian users reported a regression after updating to kernel version 5.10.247. Commit f0982400648a ("fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds"), a backport of upstream commit 3637d34b35b2, depends on vc_data::vc_font.charcount being initialised correctly. However, before commit a1ac250a82a5 ("fbcon: Avoid using FNTCHARCNT() and hard-coded built-in font charcount") in 5.11, this member was set to 256 for VTs initially created with a built-in font and 0 for VTs initially created with a user font. Since Debian normally sets a user font before creating VTs 2 and up, those additional VTs became unusable. VT 1 also doesn't work correctly if the user font has > 256 characters, and the bounds check is ineffective if it has < 256 characters. This can be fixed by backporting the following commits from 5.11: 7a089ec7d77f console: Delete unused con_font_copy() callback implementations 259a252c1f4e console: Delete dummy con_font_set() and con_font_default() callback implementations 4ee573086bd8 Fonts: Add charcount field to font_desc 4497364e5f61 parisc/sticore: Avoid hard-coding built-in font charcount a1ac250a82a5 fbcon: Avoid using FNTCHARCNT() and hard-coded built-in font charcount These all apply without fuzz and builds cleanly for x86_64 and parisc64. I tested on x86_64 that: - VT 2 works again - bit_putcs_aligned() is setting charcnt = 256 - After loading a font with 512 characters, bit_putcs_aligned() sets charcnt = 512 and is able to display characters at positions >= 256 Ben. -- Ben Hutchings Man invented language to satisfy his deep need to complain. - Lily Tomlin

5 days, 23 hours

[PATCH v2] drm/bridge: synopsys: dw-dp: return when attach bridge fail

by Osama Abdelkader

When drm_bridge_attach() fails, the function should return an error instead of continuing execution. Fixes: 86eecc3a9c2e ("drm/bridge: synopsys: Add DW DPTX Controller support library") Cc: stable(a)vger.kernel.org Signed-off-by: Osama Abdelkader <osama.abdelkader(a)gmail.com> --- v2: use concise error message add Fixes and Cc tags --- drivers/gpu/drm/bridge/synopsys/dw-dp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c index 82aaf74e1bc0..bc311a596dff 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c @@ -2063,7 +2063,7 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder, ret = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR); if (ret) - dev_err_probe(dev, ret, "Failed to attach bridge\n"); + return ERR_PTR(dev_err_probe(dev, ret, "Failed to attach bridge\n")); dw_dp_init_hw(dp); -- 2.43.0

5 days, 23 hours

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