From 779055842da5b2e508f3ccf9a8153cb1f704f566 Mon Sep 17 00:00:00 2001 From: Souptick Joarder Date: Sun, 6 Sep 2020 12:21:53 +0530 Subject: [PATCH 1/6] xen/gntdev.c: Mark pages as dirty There seems to be a bug in the original code when gntdev_get_page() is called with writeable=true then the page needs to be marked dirty before being put. To address this, a bool writeable is added in gnt_dev_copy_batch, set it in gntdev_grant_copy_seg() (and drop `writeable` argument to gntdev_get_page()) and then, based on batch->writeable, use set_page_dirty_lock(). Fixes: a4cdb556cae0 (xen/gntdev: add ioctl for grant copy) Suggested-by: Boris Ostrovsky Signed-off-by: Souptick Joarder Cc: John Hubbard Cc: Boris Ostrovsky Cc: Juergen Gross Cc: David Vrabel Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1599375114-32360-1-git-send-email-jrdr.linux@gmail.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/gntdev.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 64a9025a87bee..1f32db7b72b2c 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -720,17 +720,18 @@ struct gntdev_copy_batch { s16 __user *status[GNTDEV_COPY_BATCH]; unsigned int nr_ops; unsigned int nr_pages; + bool writeable; }; static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, - bool writeable, unsigned long *gfn) + unsigned long *gfn) { unsigned long addr = (unsigned long)virt; struct page *page; unsigned long xen_pfn; int ret; - ret = get_user_pages_fast(addr, 1, writeable ? FOLL_WRITE : 0, &page); + ret = get_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); if (ret < 0) return ret; @@ -746,9 +747,13 @@ static void gntdev_put_pages(struct gntdev_copy_batch *batch) { unsigned int i; - for (i = 0; i < batch->nr_pages; i++) + for (i = 0; i < batch->nr_pages; i++) { + if (batch->writeable && !PageDirty(batch->pages[i])) + set_page_dirty_lock(batch->pages[i]); put_page(batch->pages[i]); + } batch->nr_pages = 0; + batch->writeable = false; } static int gntdev_copy(struct gntdev_copy_batch *batch) @@ -837,8 +842,9 @@ static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, virt = seg->source.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); + batch->writeable = false; - ret = gntdev_get_page(batch, virt, false, &gfn); + ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret; @@ -856,8 +862,9 @@ static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, virt = seg->dest.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); + batch->writeable = true; - ret = gntdev_get_page(batch, virt, true, &gfn); + ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret; From d6bbc2ff68fd22dd972c684921ea348ed7ffcbb2 Mon Sep 17 00:00:00 2001 From: Souptick Joarder Date: Sun, 6 Sep 2020 12:21:54 +0530 Subject: [PATCH 2/6] xen/gntdev.c: Convert get_user_pages*() to pin_user_pages*() In 2019, we introduced pin_user_pages*() and now we are converting get_user_pages*() to the new API as appropriate. [1] & [2] could be referred for more information. This is case 5 as per document [1]. [1] Documentation/core-api/pin_user_pages.rst [2] "Explicit pinning of user-space pages": https://lwn.net/Articles/807108/ Signed-off-by: Souptick Joarder Cc: John Hubbard Cc: Boris Ostrovsky Cc: Juergen Gross Cc: David Vrabel Link: https://lore.kernel.org/r/1599375114-32360-2-git-send-email-jrdr.linux@gmail.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky --- drivers/xen/gntdev.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 1f32db7b72b2c..a36b71286bcf8 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -731,7 +731,7 @@ static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, unsigned long xen_pfn; int ret; - ret = get_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); + ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); if (ret < 0) return ret; @@ -745,13 +745,7 @@ static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, static void gntdev_put_pages(struct gntdev_copy_batch *batch) { - unsigned int i; - - for (i = 0; i < batch->nr_pages; i++) { - if (batch->writeable && !PageDirty(batch->pages[i])) - set_page_dirty_lock(batch->pages[i]); - put_page(batch->pages[i]); - } + unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); batch->nr_pages = 0; batch->writeable = false; } From bba91dd6d70b7aa239280dc095a461bc064c98a5 Mon Sep 17 00:00:00 2001 From: Jing Xiangfeng Date: Sat, 19 Sep 2020 11:17:02 +0800 Subject: [PATCH 3/6] xen: remove redundant initialization of variable ret After commit 9f51c05dc41a ("pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock"), the variable ret is being initialized with '-ENOMEM' that is meaningless. So remove it. Signed-off-by: Jing Xiangfeng Link: https://lore.kernel.org/r/20200919031702.32192-1-jingxiangfeng@huawei.com Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky --- drivers/xen/pvcalls-front.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 72d725a0ab5ce..7984645b59563 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -371,7 +371,7 @@ static int alloc_active_ring(struct sock_mapping *map) static int create_active(struct sock_mapping *map, evtchn_port_t *evtchn) { void *bytes; - int ret = -ENOMEM, irq = -1, i; + int ret, irq = -1, i; *evtchn = 0; init_waitqueue_head(&map->active.inflight_conn_req); From f88af7229f6f22ce7313c11a0bbb9c88317b7c5e Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 24 Sep 2020 16:49:55 -0700 Subject: [PATCH 4/6] xen/arm: do not setup the runstate info page if kpti is enabled The VCPUOP_register_runstate_memory_area hypercall takes a virtual address of a buffer as a parameter. The semantics of the hypercall are such that the virtual address should always be valid. When KPTI is enabled and we are running userspace code, the virtual address is not valid, thus, Linux is violating the semantics of VCPUOP_register_runstate_memory_area. Do not call VCPUOP_register_runstate_memory_area when KPTI is enabled. Signed-off-by: Stefano Stabellini CC: Bertrand Marquis CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Link: https://lore.kernel.org/r/20200924234955.15455-1-sstabellini@kernel.org Reviewed-by: Bertrand Marquis Signed-off-by: Boris Ostrovsky --- arch/arm/include/asm/xen/page.h | 5 +++++ arch/arm/xen/enlighten.c | 6 ++++-- arch/arm64/include/asm/xen/page.h | 6 ++++++ 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 31bbc803cecb2..dc7f6e91aafad 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -1 +1,6 @@ #include + +static inline bool xen_kernel_unmapped_at_usr(void) +{ + return false; +} diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index e93145d72c26e..ea76562af1e9a 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -158,7 +158,8 @@ static int xen_starting_cpu(unsigned int cpu) BUG_ON(err); per_cpu(xen_vcpu, cpu) = vcpup; - xen_setup_runstate_info(cpu); + if (!xen_kernel_unmapped_at_usr()) + xen_setup_runstate_info(cpu); after_register_vcpu_info: enable_percpu_irq(xen_events_irq, 0); @@ -387,7 +388,8 @@ static int __init xen_guest_init(void) return -EINVAL; } - xen_time_setup_guest(); + if (!xen_kernel_unmapped_at_usr()) + xen_time_setup_guest(); if (xen_initial_domain()) pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier); diff --git a/arch/arm64/include/asm/xen/page.h b/arch/arm64/include/asm/xen/page.h index 31bbc803cecb2..dffdc773221bf 100644 --- a/arch/arm64/include/asm/xen/page.h +++ b/arch/arm64/include/asm/xen/page.h @@ -1 +1,7 @@ #include +#include + +static inline bool xen_kernel_unmapped_at_usr(void) +{ + return arm64_kernel_unmapped_at_el0(); +} From d759af38572f97321112a0852353613d18126038 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 25 Sep 2020 16:07:51 +0200 Subject: [PATCH 5/6] x86/xen: disable Firmware First mode for correctable memory errors When running as Xen dom0 the kernel isn't responsible for selecting the error handling mode, this should be handled by the hypervisor. So disable setting FF mode when running as Xen pv guest. Not doing so might result in boot splats like: [ 7.509696] HEST: Enabling Firmware First mode for corrected errors. [ 7.510382] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 2. [ 7.510383] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 3. [ 7.510384] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 4. [ 7.510384] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 5. [ 7.510385] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 6. [ 7.510386] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 7. [ 7.510386] mce: [Firmware Bug]: Ignoring request to disable invalid MCA bank 8. Reason is that the HEST ACPI table contains the real number of MCA banks, while the hypervisor is emulating only 2 banks for guests. Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20200925140751.31381-1-jgross@suse.com Signed-off-by: Boris Ostrovsky --- arch/x86/xen/enlighten_pv.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 22e741e0b10c3..351ac1a9a119f 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1376,6 +1376,15 @@ asmlinkage __visible void __init xen_start_kernel(void) x86_init.mpparse.get_smp_config = x86_init_uint_noop; xen_boot_params_init_edd(); + +#ifdef CONFIG_ACPI + /* + * Disable selecting "Firmware First mode" for correctable + * memory errors, as this is the duty of the hypervisor to + * decide. + */ + acpi_disable_cmcff = 1; +#endif } if (!boot_params.screen_info.orig_video_isVGA) From 32118f97f41d26a2447118fa956715cb4bd1bdac Mon Sep 17 00:00:00 2001 From: Hui Su Date: Mon, 28 Sep 2020 01:28:36 +0800 Subject: [PATCH 6/6] x86/xen: Fix typo in xen_pagetable_p2m_free() Fix typo in xen_pagetable_p2m_free(): s/Fortunatly/Fortunately Signed-off-by: Hui Su Link: https://lore.kernel.org/r/20200927172836.GA7423@rlk [boris: reword commit message slightly] Signed-off-by: Boris Ostrovsky --- arch/x86/xen/mmu_pv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 3273c985d3dd9..fbee8f50088b8 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1149,7 +1149,7 @@ static void __init xen_pagetable_p2m_free(void) * We could be in __ka space. * We roundup to the PMD, which means that if anybody at this stage is * using the __ka address of xen_start_info or - * xen_start_info->shared_info they are in going to crash. Fortunatly + * xen_start_info->shared_info they are in going to crash. Fortunately * we have already revectored in xen_setup_kernel_pagetable. */ size = roundup(size, PMD_SIZE);