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FAILED: patch "[PATCH] xen/events: Return -EEXIST for bound VIRQs" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 07ce121d93a5e5fb2440a24da3dbf408fcee978e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101625-rebalance-humbling-87a2@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 07ce121d93a5e5fb2440a24da3dbf408fcee978e Mon Sep 17 00:00:00 2001 From: Jason Andryuk <jason.andryuk(a)amd.com> Date: Wed, 27 Aug 2025 20:36:02 -0400 Subject: [PATCH] xen/events: Return -EEXIST for bound VIRQs Change find_virq() to return -EEXIST when a VIRQ is bound to a different CPU than the one passed in. With that, remove the BUG_ON() from bind_virq_to_irq() to propogate the error upwards. Some VIRQs are per-cpu, but others are per-domain or global. Those must be bound to CPU0 and can then migrate elsewhere. The lookup for per-domain and global will probably fail when migrated off CPU 0, especially when the current CPU is tracked. This now returns -EEXIST instead of BUG_ON(). A second call to bind a per-domain or global VIRQ is not expected, but make it non-fatal to avoid trying to look up the irq, since we don't know which per_cpu(virq_to_irq) it will be in. Cc: stable(a)vger.kernel.org Signed-off-by: Jason Andryuk <jason.andryuk(a)amd.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Signed-off-by: Juergen Gross <jgross(a)suse.com> Message-ID: <20250828003604.8949-3-jason.andryuk(a)amd.com> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 374231d84e4f..b060b5a95f45 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1314,10 +1314,12 @@ int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev, } EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi); -static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) +static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn, + bool percpu) { struct evtchn_status status; evtchn_port_t port; + bool exists = false; memset(&status, 0, sizeof(status)); for (port = 0; port < xen_evtchn_max_channels(); port++) { @@ -1330,12 +1332,16 @@ static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) continue; if (status.status != EVTCHNSTAT_virq) continue; - if (status.u.virq == virq && status.vcpu == xen_vcpu_nr(cpu)) { + if (status.u.virq != virq) + continue; + if (status.vcpu == xen_vcpu_nr(cpu)) { *evtchn = port; return 0; + } else if (!percpu) { + exists = true; } } - return -ENOENT; + return exists ? -EEXIST : -ENOENT; } /** @@ -1382,8 +1388,11 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu) evtchn = bind_virq.port; else { if (ret == -EEXIST) - ret = find_virq(virq, cpu, &evtchn); - BUG_ON(ret < 0); + ret = find_virq(virq, cpu, &evtchn, percpu); + if (ret) { + __unbind_from_irq(info, info->irq); + goto out; + } } ret = xen_irq_info_virq_setup(info, cpu, evtchn, virq);

2 months, 1 week

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FAILED: patch "[PATCH] xen/events: Return -EEXIST for bound VIRQs" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 07ce121d93a5e5fb2440a24da3dbf408fcee978e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101625-gully-disaster-8717@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 07ce121d93a5e5fb2440a24da3dbf408fcee978e Mon Sep 17 00:00:00 2001 From: Jason Andryuk <jason.andryuk(a)amd.com> Date: Wed, 27 Aug 2025 20:36:02 -0400 Subject: [PATCH] xen/events: Return -EEXIST for bound VIRQs Change find_virq() to return -EEXIST when a VIRQ is bound to a different CPU than the one passed in. With that, remove the BUG_ON() from bind_virq_to_irq() to propogate the error upwards. Some VIRQs are per-cpu, but others are per-domain or global. Those must be bound to CPU0 and can then migrate elsewhere. The lookup for per-domain and global will probably fail when migrated off CPU 0, especially when the current CPU is tracked. This now returns -EEXIST instead of BUG_ON(). A second call to bind a per-domain or global VIRQ is not expected, but make it non-fatal to avoid trying to look up the irq, since we don't know which per_cpu(virq_to_irq) it will be in. Cc: stable(a)vger.kernel.org Signed-off-by: Jason Andryuk <jason.andryuk(a)amd.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Signed-off-by: Juergen Gross <jgross(a)suse.com> Message-ID: <20250828003604.8949-3-jason.andryuk(a)amd.com> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 374231d84e4f..b060b5a95f45 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1314,10 +1314,12 @@ int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev, } EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi); -static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) +static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn, + bool percpu) { struct evtchn_status status; evtchn_port_t port; + bool exists = false; memset(&status, 0, sizeof(status)); for (port = 0; port < xen_evtchn_max_channels(); port++) { @@ -1330,12 +1332,16 @@ static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) continue; if (status.status != EVTCHNSTAT_virq) continue; - if (status.u.virq == virq && status.vcpu == xen_vcpu_nr(cpu)) { + if (status.u.virq != virq) + continue; + if (status.vcpu == xen_vcpu_nr(cpu)) { *evtchn = port; return 0; + } else if (!percpu) { + exists = true; } } - return -ENOENT; + return exists ? -EEXIST : -ENOENT; } /** @@ -1382,8 +1388,11 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu) evtchn = bind_virq.port; else { if (ret == -EEXIST) - ret = find_virq(virq, cpu, &evtchn); - BUG_ON(ret < 0); + ret = find_virq(virq, cpu, &evtchn, percpu); + if (ret) { + __unbind_from_irq(info, info->irq); + goto out; + } } ret = xen_irq_info_virq_setup(info, cpu, evtchn, virq);

2 months, 1 week

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FAILED: patch "[PATCH] xen/events: Return -EEXIST for bound VIRQs" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 07ce121d93a5e5fb2440a24da3dbf408fcee978e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101624-yield-grime-5287@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 07ce121d93a5e5fb2440a24da3dbf408fcee978e Mon Sep 17 00:00:00 2001 From: Jason Andryuk <jason.andryuk(a)amd.com> Date: Wed, 27 Aug 2025 20:36:02 -0400 Subject: [PATCH] xen/events: Return -EEXIST for bound VIRQs Change find_virq() to return -EEXIST when a VIRQ is bound to a different CPU than the one passed in. With that, remove the BUG_ON() from bind_virq_to_irq() to propogate the error upwards. Some VIRQs are per-cpu, but others are per-domain or global. Those must be bound to CPU0 and can then migrate elsewhere. The lookup for per-domain and global will probably fail when migrated off CPU 0, especially when the current CPU is tracked. This now returns -EEXIST instead of BUG_ON(). A second call to bind a per-domain or global VIRQ is not expected, but make it non-fatal to avoid trying to look up the irq, since we don't know which per_cpu(virq_to_irq) it will be in. Cc: stable(a)vger.kernel.org Signed-off-by: Jason Andryuk <jason.andryuk(a)amd.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Signed-off-by: Juergen Gross <jgross(a)suse.com> Message-ID: <20250828003604.8949-3-jason.andryuk(a)amd.com> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 374231d84e4f..b060b5a95f45 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1314,10 +1314,12 @@ int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev, } EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi); -static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) +static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn, + bool percpu) { struct evtchn_status status; evtchn_port_t port; + bool exists = false; memset(&status, 0, sizeof(status)); for (port = 0; port < xen_evtchn_max_channels(); port++) { @@ -1330,12 +1332,16 @@ static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) continue; if (status.status != EVTCHNSTAT_virq) continue; - if (status.u.virq == virq && status.vcpu == xen_vcpu_nr(cpu)) { + if (status.u.virq != virq) + continue; + if (status.vcpu == xen_vcpu_nr(cpu)) { *evtchn = port; return 0; + } else if (!percpu) { + exists = true; } } - return -ENOENT; + return exists ? -EEXIST : -ENOENT; } /** @@ -1382,8 +1388,11 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu) evtchn = bind_virq.port; else { if (ret == -EEXIST) - ret = find_virq(virq, cpu, &evtchn); - BUG_ON(ret < 0); + ret = find_virq(virq, cpu, &evtchn, percpu); + if (ret) { + __unbind_from_irq(info, info->irq); + goto out; + } } ret = xen_irq_info_virq_setup(info, cpu, evtchn, virq);

2 months, 1 week

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FAILED: patch "[PATCH] KVM: SVM: Re-load current, not host, TSC_AUX on #VMEXIT from" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 29da8c823abffdacb71c7c07ec48fcf9eb38757c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101656-durable-outmost-5a6e@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 29da8c823abffdacb71c7c07ec48fcf9eb38757c Mon Sep 17 00:00:00 2001 From: Hou Wenlong <houwenlong.hwl(a)antgroup.com> Date: Tue, 23 Sep 2025 08:37:38 -0700 Subject: [PATCH] KVM: SVM: Re-load current, not host, TSC_AUX on #VMEXIT from SEV-ES guest Prior to running an SEV-ES guest, set TSC_AUX in the host save area to the current value in hardware, as tracked by the user return infrastructure, instead of always loading the host's desired value for the CPU. If the pCPU is also running a non-SEV-ES vCPU, loading the host's value on #VMEXIT could clobber the other vCPU's value, e.g. if the SEV-ES vCPU preempted the non-SEV-ES vCPU, in which case KVM expects the other vCPU's TSC_AUX value to be resident in hardware. Note, unlike TDX, which blindly _zeroes_ TSC_AUX on TD-Exit, SEV-ES CPUs can load an arbitrary value. Stuff the current value in the host save area instead of refreshing the user return cache so that KVM doesn't need to track whether or not the vCPU actually enterred the guest and thus loaded TSC_AUX from the host save area. Opportunistically tag tsc_aux_uret_slot as read-only after init to guard against unexpected modifications, and to make it obvious that using the variable in sev_es_prepare_switch_to_guest() is safe. Fixes: 916e3e5f26ab ("KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX") Cc: stable(a)vger.kernel.org Suggested-by: Lai Jiangshan <jiangshan.ljs(a)antgroup.com> Signed-off-by: Hou Wenlong <houwenlong.hwl(a)antgroup.com> [sean: handle the SEV-ES case in sev_es_prepare_switch_to_guest()] Reviewed-by: Xiaoyao Li <xiaoyao.li(a)intel.com> Link: https://lore.kernel.org/r/20250923153738.1875174-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc(a)google.com> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 019d920fe442..5529e4c3362b 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -4666,6 +4666,16 @@ void sev_es_prepare_switch_to_guest(struct vcpu_svm *svm, struct sev_es_save_are hostsa->dr2_addr_mask = amd_get_dr_addr_mask(2); hostsa->dr3_addr_mask = amd_get_dr_addr_mask(3); } + + /* + * TSC_AUX is always virtualized for SEV-ES guests when the feature is + * available, i.e. TSC_AUX is loaded on #VMEXIT from the host save area. + * Set the save area to the current hardware value, i.e. the current + * user return value, so that the correct value is restored on #VMEXIT. + */ + if (cpu_feature_enabled(X86_FEATURE_V_TSC_AUX) && + !WARN_ON_ONCE(tsc_aux_uret_slot < 0)) + hostsa->tsc_aux = kvm_get_user_return_msr(tsc_aux_uret_slot); } void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index b237b4081c91..6f486fb82144 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -195,7 +195,7 @@ static DEFINE_MUTEX(vmcb_dump_mutex); * RDTSCP and RDPID are not used in the kernel, specifically to allow KVM to * defer the restoration of TSC_AUX until the CPU returns to userspace. */ -static int tsc_aux_uret_slot __read_mostly = -1; +int tsc_aux_uret_slot __ro_after_init = -1; static int get_npt_level(void) { @@ -577,18 +577,6 @@ static int svm_enable_virtualization_cpu(void) amd_pmu_enable_virt(); - /* - * If TSC_AUX virtualization is supported, TSC_AUX becomes a swap type - * "B" field (see sev_es_prepare_switch_to_guest()) for SEV-ES guests. - * Since Linux does not change the value of TSC_AUX once set, prime the - * TSC_AUX field now to avoid a RDMSR on every vCPU run. - */ - if (boot_cpu_has(X86_FEATURE_V_TSC_AUX)) { - u32 __maybe_unused msr_hi; - - rdmsr(MSR_TSC_AUX, sev_es_host_save_area(sd)->tsc_aux, msr_hi); - } - return 0; } @@ -1406,10 +1394,10 @@ static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu) __svm_write_tsc_multiplier(vcpu->arch.tsc_scaling_ratio); /* - * TSC_AUX is always virtualized for SEV-ES guests when the feature is - * available. The user return MSR support is not required in this case - * because TSC_AUX is restored on #VMEXIT from the host save area - * (which has been initialized in svm_enable_virtualization_cpu()). + * TSC_AUX is always virtualized (context switched by hardware) for + * SEV-ES guests when the feature is available. For non-SEV-ES guests, + * context switch TSC_AUX via the user_return MSR infrastructure (not + * all CPUs support TSC_AUX virtualization). */ if (likely(tsc_aux_uret_slot >= 0) && (!boot_cpu_has(X86_FEATURE_V_TSC_AUX) || !sev_es_guest(vcpu->kvm))) @@ -3004,8 +2992,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) * TSC_AUX is always virtualized for SEV-ES guests when the * feature is available. The user return MSR support is not * required in this case because TSC_AUX is restored on #VMEXIT - * from the host save area (which has been initialized in - * svm_enable_virtualization_cpu()). + * from the host save area. */ if (boot_cpu_has(X86_FEATURE_V_TSC_AUX) && sev_es_guest(vcpu->kvm)) break; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 10d5cbc259e1..ec3fb318ca83 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -52,6 +52,8 @@ extern bool x2avic_enabled; extern bool vnmi; extern int lbrv; +extern int tsc_aux_uret_slot __ro_after_init; + /* * Clean bits in VMCB. * VMCB_ALL_CLEAN_MASK might also need to

2 months, 1 week

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FAILED: patch "[PATCH] xen/events: Return -EEXIST for bound VIRQs" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 07ce121d93a5e5fb2440a24da3dbf408fcee978e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101657-dragonish-scarcity-3be3@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 07ce121d93a5e5fb2440a24da3dbf408fcee978e Mon Sep 17 00:00:00 2001 From: Jason Andryuk <jason.andryuk(a)amd.com> Date: Wed, 27 Aug 2025 20:36:02 -0400 Subject: [PATCH] xen/events: Return -EEXIST for bound VIRQs Change find_virq() to return -EEXIST when a VIRQ is bound to a different CPU than the one passed in. With that, remove the BUG_ON() from bind_virq_to_irq() to propogate the error upwards. Some VIRQs are per-cpu, but others are per-domain or global. Those must be bound to CPU0 and can then migrate elsewhere. The lookup for per-domain and global will probably fail when migrated off CPU 0, especially when the current CPU is tracked. This now returns -EEXIST instead of BUG_ON(). A second call to bind a per-domain or global VIRQ is not expected, but make it non-fatal to avoid trying to look up the irq, since we don't know which per_cpu(virq_to_irq) it will be in. Cc: stable(a)vger.kernel.org Signed-off-by: Jason Andryuk <jason.andryuk(a)amd.com> Reviewed-by: Juergen Gross <jgross(a)suse.com> Signed-off-by: Juergen Gross <jgross(a)suse.com> Message-ID: <20250828003604.8949-3-jason.andryuk(a)amd.com> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 374231d84e4f..b060b5a95f45 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1314,10 +1314,12 @@ int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev, } EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi); -static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) +static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn, + bool percpu) { struct evtchn_status status; evtchn_port_t port; + bool exists = false; memset(&status, 0, sizeof(status)); for (port = 0; port < xen_evtchn_max_channels(); port++) { @@ -1330,12 +1332,16 @@ static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) continue; if (status.status != EVTCHNSTAT_virq) continue; - if (status.u.virq == virq && status.vcpu == xen_vcpu_nr(cpu)) { + if (status.u.virq != virq) + continue; + if (status.vcpu == xen_vcpu_nr(cpu)) { *evtchn = port; return 0; + } else if (!percpu) { + exists = true; } } - return -ENOENT; + return exists ? -EEXIST : -ENOENT; } /** @@ -1382,8 +1388,11 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu) evtchn = bind_virq.port; else { if (ret == -EEXIST) - ret = find_virq(virq, cpu, &evtchn); - BUG_ON(ret < 0); + ret = find_virq(virq, cpu, &evtchn, percpu); + if (ret) { + __unbind_from_irq(info, info->irq); + goto out; + } } ret = xen_irq_info_virq_setup(info, cpu, evtchn, virq);

2 months, 1 week

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FAILED: patch "[PATCH] KVM: SVM: Re-load current, not host, TSC_AUX on #VMEXIT from" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 29da8c823abffdacb71c7c07ec48fcf9eb38757c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101638-lively-electable-a835@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 29da8c823abffdacb71c7c07ec48fcf9eb38757c Mon Sep 17 00:00:00 2001 From: Hou Wenlong <houwenlong.hwl(a)antgroup.com> Date: Tue, 23 Sep 2025 08:37:38 -0700 Subject: [PATCH] KVM: SVM: Re-load current, not host, TSC_AUX on #VMEXIT from SEV-ES guest Prior to running an SEV-ES guest, set TSC_AUX in the host save area to the current value in hardware, as tracked by the user return infrastructure, instead of always loading the host's desired value for the CPU. If the pCPU is also running a non-SEV-ES vCPU, loading the host's value on #VMEXIT could clobber the other vCPU's value, e.g. if the SEV-ES vCPU preempted the non-SEV-ES vCPU, in which case KVM expects the other vCPU's TSC_AUX value to be resident in hardware. Note, unlike TDX, which blindly _zeroes_ TSC_AUX on TD-Exit, SEV-ES CPUs can load an arbitrary value. Stuff the current value in the host save area instead of refreshing the user return cache so that KVM doesn't need to track whether or not the vCPU actually enterred the guest and thus loaded TSC_AUX from the host save area. Opportunistically tag tsc_aux_uret_slot as read-only after init to guard against unexpected modifications, and to make it obvious that using the variable in sev_es_prepare_switch_to_guest() is safe. Fixes: 916e3e5f26ab ("KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX") Cc: stable(a)vger.kernel.org Suggested-by: Lai Jiangshan <jiangshan.ljs(a)antgroup.com> Signed-off-by: Hou Wenlong <houwenlong.hwl(a)antgroup.com> [sean: handle the SEV-ES case in sev_es_prepare_switch_to_guest()] Reviewed-by: Xiaoyao Li <xiaoyao.li(a)intel.com> Link: https://lore.kernel.org/r/20250923153738.1875174-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc(a)google.com> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 019d920fe442..5529e4c3362b 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -4666,6 +4666,16 @@ void sev_es_prepare_switch_to_guest(struct vcpu_svm *svm, struct sev_es_save_are hostsa->dr2_addr_mask = amd_get_dr_addr_mask(2); hostsa->dr3_addr_mask = amd_get_dr_addr_mask(3); } + + /* + * TSC_AUX is always virtualized for SEV-ES guests when the feature is + * available, i.e. TSC_AUX is loaded on #VMEXIT from the host save area. + * Set the save area to the current hardware value, i.e. the current + * user return value, so that the correct value is restored on #VMEXIT. + */ + if (cpu_feature_enabled(X86_FEATURE_V_TSC_AUX) && + !WARN_ON_ONCE(tsc_aux_uret_slot < 0)) + hostsa->tsc_aux = kvm_get_user_return_msr(tsc_aux_uret_slot); } void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index b237b4081c91..6f486fb82144 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -195,7 +195,7 @@ static DEFINE_MUTEX(vmcb_dump_mutex); * RDTSCP and RDPID are not used in the kernel, specifically to allow KVM to * defer the restoration of TSC_AUX until the CPU returns to userspace. */ -static int tsc_aux_uret_slot __read_mostly = -1; +int tsc_aux_uret_slot __ro_after_init = -1; static int get_npt_level(void) { @@ -577,18 +577,6 @@ static int svm_enable_virtualization_cpu(void) amd_pmu_enable_virt(); - /* - * If TSC_AUX virtualization is supported, TSC_AUX becomes a swap type - * "B" field (see sev_es_prepare_switch_to_guest()) for SEV-ES guests. - * Since Linux does not change the value of TSC_AUX once set, prime the - * TSC_AUX field now to avoid a RDMSR on every vCPU run. - */ - if (boot_cpu_has(X86_FEATURE_V_TSC_AUX)) { - u32 __maybe_unused msr_hi; - - rdmsr(MSR_TSC_AUX, sev_es_host_save_area(sd)->tsc_aux, msr_hi); - } - return 0; } @@ -1406,10 +1394,10 @@ static void svm_prepare_switch_to_guest(struct kvm_vcpu *vcpu) __svm_write_tsc_multiplier(vcpu->arch.tsc_scaling_ratio); /* - * TSC_AUX is always virtualized for SEV-ES guests when the feature is - * available. The user return MSR support is not required in this case - * because TSC_AUX is restored on #VMEXIT from the host save area - * (which has been initialized in svm_enable_virtualization_cpu()). + * TSC_AUX is always virtualized (context switched by hardware) for + * SEV-ES guests when the feature is available. For non-SEV-ES guests, + * context switch TSC_AUX via the user_return MSR infrastructure (not + * all CPUs support TSC_AUX virtualization). */ if (likely(tsc_aux_uret_slot >= 0) && (!boot_cpu_has(X86_FEATURE_V_TSC_AUX) || !sev_es_guest(vcpu->kvm))) @@ -3004,8 +2992,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) * TSC_AUX is always virtualized for SEV-ES guests when the * feature is available. The user return MSR support is not * required in this case because TSC_AUX is restored on #VMEXIT - * from the host save area (which has been initialized in - * svm_enable_virtualization_cpu()). + * from the host save area. */ if (boot_cpu_has(X86_FEATURE_V_TSC_AUX) && sev_es_guest(vcpu->kvm)) break; diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 10d5cbc259e1..ec3fb318ca83 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -52,6 +52,8 @@ extern bool x2avic_enabled; extern bool vnmi; extern int lbrv; +extern int tsc_aux_uret_slot __ro_after_init; + /* * Clean bits in VMCB. * VMCB_ALL_CLEAN_MASK might also need to

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FAILED: patch "[PATCH] arm64: kprobes: call set_memory_rox() for kprobe page" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 195a1b7d8388c0ec2969a39324feb8bebf9bb907 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101631-croon-serving-8366@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 195a1b7d8388c0ec2969a39324feb8bebf9bb907 Mon Sep 17 00:00:00 2001 From: Yang Shi <yang(a)os.amperecomputing.com> Date: Thu, 18 Sep 2025 09:23:49 -0700 Subject: [PATCH] arm64: kprobes: call set_memory_rox() for kprobe page The kprobe page is allocated by execmem allocator with ROX permission. It needs to call set_memory_rox() to set proper permission for the direct map too. It was missed. Fixes: 10d5e97c1bf8 ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page") Cc: <stable(a)vger.kernel.org> Signed-off-by: Yang Shi <yang(a)os.amperecomputing.com> Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com> Signed-off-by: Will Deacon <will(a)kernel.org> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index 0c5d408afd95..8ab6104a4883 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -10,6 +10,7 @@ #define pr_fmt(fmt) "kprobes: " fmt +#include <linux/execmem.h> #include <linux/extable.h> #include <linux/kasan.h> #include <linux/kernel.h> @@ -41,6 +42,17 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); static void __kprobes post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *); +void *alloc_insn_page(void) +{ + void *addr; + + addr = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE); + if (!addr) + return NULL; + set_memory_rox((unsigned long)addr, 1); + return addr; +} + static void __kprobes arch_prepare_ss_slot(struct kprobe *p) { kprobe_opcode_t *addr = p->ainsn.xol_insn;

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[PATCH 6.12.y] KVM: x86: Advertise SRSO_USER_KERNEL_NO to userspace

by Harshit Mogalapalli

From: "Borislav Petkov (AMD)" <bp(a)alien8.de> [ Upstream commit 716f86b523d8ec3c17015ee0b03135c7aa6f2f08 ] SRSO_USER_KERNEL_NO denotes whether the CPU is affected by SRSO across user/kernel boundaries. Advertise it to guest userspace. Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Nikolay Borisov <nik.borisov(a)suse.com> Link: https://lore.kernel.org/r/20241202120416.6054-3-bp@kernel.org Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com> --- Boris Ostrovsky suggested that we backport this commit to 6.12.y as we have commit: 6f0f23ef76be ("KVM: x86: Add IBPB_BRTYPE support") in 6.12.y Hi borislav: Can you please ACK before stable maintainers pick this ? --- arch/x86/kvm/cpuid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 8f587c5bb6bc..a7a1486ce270 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -816,7 +816,7 @@ void kvm_set_cpu_caps(void) F(NO_NESTED_DATA_BP) | F(LFENCE_RDTSC) | 0 /* SmmPgCfgLock */ | F(VERW_CLEAR) | F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */ | - F(WRMSR_XX_BASE_NS) + F(WRMSR_XX_BASE_NS) | F(SRSO_USER_KERNEL_NO) ); kvm_cpu_cap_check_and_set(X86_FEATURE_SBPB); -- 2.50.1

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New October Order. 41380 Thursday, October 16, 2025 at 05:19:56 AM

by Purchase - PathnSitu 686

Hi Stable, Please provide a quote for your products: Include: 1.Pricing (per unit) 2.Delivery cost & timeline 3.Quote expiry date Deadline: October Thanks! Danny Peddinti PathnSitu Trading

2 months, 1 week

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FAILED: patch "[PATCH] rseq: Protect event mask against membarrier IPI" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 6eb350a2233100a283f882c023e5ad426d0ed63b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101555-glimpse-gauntlet-5c2a@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6eb350a2233100a283f882c023e5ad426d0ed63b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx(a)linutronix.de> Date: Wed, 13 Aug 2025 17:02:30 +0200 Subject: [PATCH] rseq: Protect event mask against membarrier IPI rseq_need_restart() reads and clears task::rseq_event_mask with preemption disabled to guard against the scheduler. But membarrier() uses an IPI and sets the PREEMPT bit in the event mask from the IPI, which leaves that RMW operation unprotected. Use guard(irq) if CONFIG_MEMBARRIER is enabled to fix that. Fixes: 2a36ab717e8f ("rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ") Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Reviewed-by: Boqun Feng <boqun.feng(a)gmail.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: stable(a)vger.kernel.org diff --git a/include/linux/rseq.h b/include/linux/rseq.h index bc8af3eb5598..1fbeb61babeb 100644 --- a/include/linux/rseq.h +++ b/include/linux/rseq.h @@ -7,6 +7,12 @@ #include <linux/preempt.h> #include <linux/sched.h> +#ifdef CONFIG_MEMBARRIER +# define RSEQ_EVENT_GUARD irq +#else +# define RSEQ_EVENT_GUARD preempt +#endif + /* * Map the event mask on the user-space ABI enum rseq_cs_flags * for direct mask checks. @@ -41,9 +47,8 @@ static inline void rseq_handle_notify_resume(struct ksignal *ksig, static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs) { - preempt_disable(); - __set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask); - preempt_enable(); + scoped_guard(RSEQ_EVENT_GUARD) + __set_bit(RSEQ_EVENT_SIGNAL_BIT, &current->rseq_event_mask); rseq_handle_notify_resume(ksig, regs); } diff --git a/kernel/rseq.c b/kernel/rseq.c index b7a1ec327e81..2452b7366b00 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -342,12 +342,12 @@ static int rseq_need_restart(struct task_struct *t, u32 cs_flags) /* * Load and clear event mask atomically with respect to - * scheduler preemption. + * scheduler preemption and membarrier IPIs. */ - preempt_disable(); - event_mask = t->rseq_event_mask; - t->rseq_event_mask = 0; - preempt_enable(); + scoped_guard(RSEQ_EVENT_GUARD) { + event_mask = t->rseq_event_mask; + t->rseq_event_mask = 0; + } return !!event_mask; }

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