From 8d693b911bb9c57009c24cb1772d205b84c7985c Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 11 Jul 2014 11:51:35 -0400 Subject: xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests. By default when CONFIG_XEN and CONFIG_XEN_PVHVM kernels are run, they will enable the PV extensions (drivers, interrupts, timers, etc) - which is the best option for the majority of use cases. However, in some cases (kexec not fully working, benchmarking) we want to disable Xen PV extensions. As such introduce the 'xen_nopv' parameter that will do it. This parameter is intended only for HVM guests as the Xen PV guests MUST boot with PV extensions. However, even if you use 'xen_nopv' on Xen PV guests it will be ignored. Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: David Vrabel --- [v2: s/off/xen_nopv/ per Boris Ostrovsky recommendation.] [v3: Add Reviewed-by] [v4: Clarify that this is only for HVM guests] --- arch/x86/xen/enlighten.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/x86/xen') diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index ffb101e45731..eb822391b84c 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1826,8 +1826,19 @@ static void __init xen_hvm_guest_init(void) xen_hvm_init_mmu_ops(); } +static bool xen_nopv = false; +static __init int xen_parse_nopv(char *arg) +{ + xen_nopv = true; + return 0; +} +early_param("xen_nopv", xen_parse_nopv); + static uint32_t __init xen_hvm_platform(void) { + if (xen_nopv) + return 0; + if (xen_pv_domain()) return 0; @@ -1836,6 +1847,8 @@ static uint32_t __init xen_hvm_platform(void) bool xen_hvm_need_lapic(void) { + if (xen_nopv) + return false; if (xen_pv_domain()) return false; if (!xen_hvm_domain()) -- cgit v1.2.1 From 162e371712768248a38646eefa71af38b6e0f8ce Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Fri, 11 Jul 2014 16:42:34 +0100 Subject: x86/xen: safely map and unmap grant frames when in atomic context arch_gnttab_map_frames() and arch_gnttab_unmap_frames() are called in atomic context but were calling alloc_vm_area() which might sleep. Also, if a driver attempts to allocate a grant ref from an interrupt and the table needs expanding, then the CPU may already by in lazy MMU mode and apply_to_page_range() will BUG when it tries to re-enable lazy MMU mode. These two functions are only used in PV guests. Introduce arch_gnttab_init() to allocates the virtual address space in advance. Avoid the use of apply_to_page_range() by using saving and using the array of PTE addresses from the alloc_vm_area() call. N.B. 'alloc_vm_area' pre-allocates the pagetable so there is no need to worry about having to do a PGD/PUD/PMD walk (like apply_to_page_range does) and we can instead do set_pte. Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk ---- [v2: Add comment about alloc_vm_area] [v3: Fix compile error found by 0-day bot] --- arch/x86/xen/grant-table.c | 148 ++++++++++++++++++++++++++++----------------- 1 file changed, 91 insertions(+), 57 deletions(-) (limited to 'arch/x86/xen') diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c index c98583588580..ebfa9b2c871d 100644 --- a/arch/x86/xen/grant-table.c +++ b/arch/x86/xen/grant-table.c @@ -36,99 +36,133 @@ #include #include +#include #include #include #include #include +#include #include -static int map_pte_fn(pte_t *pte, struct page *pmd_page, - unsigned long addr, void *data) +static struct gnttab_vm_area { + struct vm_struct *area; + pte_t **ptes; +} gnttab_shared_vm_area, gnttab_status_vm_area; + +int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, + unsigned long max_nr_gframes, + void **__shared) { - unsigned long **frames = (unsigned long **)data; + void *shared = *__shared; + unsigned long addr; + unsigned long i; - set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL)); - (*frames)++; - return 0; -} + if (shared == NULL) + *__shared = shared = gnttab_shared_vm_area.area->addr; -/* - * This function is used to map shared frames to store grant status. It is - * different from map_pte_fn above, the frames type here is uint64_t. - */ -static int map_pte_fn_status(pte_t *pte, struct page *pmd_page, - unsigned long addr, void *data) -{ - uint64_t **frames = (uint64_t **)data; + addr = (unsigned long)shared; + + for (i = 0; i < nr_gframes; i++) { + set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i], + mfn_pte(frames[i], PAGE_KERNEL)); + addr += PAGE_SIZE; + } - set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL)); - (*frames)++; return 0; } -static int unmap_pte_fn(pte_t *pte, struct page *pmd_page, - unsigned long addr, void *data) +int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, + unsigned long max_nr_gframes, + grant_status_t **__shared) { + grant_status_t *shared = *__shared; + unsigned long addr; + unsigned long i; + + if (shared == NULL) + *__shared = shared = gnttab_status_vm_area.area->addr; + + addr = (unsigned long)shared; + + for (i = 0; i < nr_gframes; i++) { + set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i], + mfn_pte(frames[i], PAGE_KERNEL)); + addr += PAGE_SIZE; + } - set_pte_at(&init_mm, addr, pte, __pte(0)); return 0; } -int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, - unsigned long max_nr_gframes, - void **__shared) +void arch_gnttab_unmap(void *shared, unsigned long nr_gframes) { - int rc; - void *shared = *__shared; + pte_t **ptes; + unsigned long addr; + unsigned long i; - if (shared == NULL) { - struct vm_struct *area = - alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL); - BUG_ON(area == NULL); - shared = area->addr; - *__shared = shared; - } + if (shared == gnttab_status_vm_area.area->addr) + ptes = gnttab_status_vm_area.ptes; + else + ptes = gnttab_shared_vm_area.ptes; - rc = apply_to_page_range(&init_mm, (unsigned long)shared, - PAGE_SIZE * nr_gframes, - map_pte_fn, &frames); - return rc; + addr = (unsigned long)shared; + + for (i = 0; i < nr_gframes; i++) { + set_pte_at(&init_mm, addr, ptes[i], __pte(0)); + addr += PAGE_SIZE; + } } -int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, - unsigned long max_nr_gframes, - grant_status_t **__shared) +static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames) { - int rc; - grant_status_t *shared = *__shared; + area->ptes = kmalloc(sizeof(pte_t *) * nr_frames, GFP_KERNEL); + if (area->ptes == NULL) + return -ENOMEM; - if (shared == NULL) { - /* No need to pass in PTE as we are going to do it - * in apply_to_page_range anyhow. */ - struct vm_struct *area = - alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL); - BUG_ON(area == NULL); - shared = area->addr; - *__shared = shared; + area->area = alloc_vm_area(PAGE_SIZE * nr_frames, area->ptes); + if (area->area == NULL) { + kfree(area->ptes); + return -ENOMEM; } - rc = apply_to_page_range(&init_mm, (unsigned long)shared, - PAGE_SIZE * nr_gframes, - map_pte_fn_status, &frames); - return rc; + return 0; } -void arch_gnttab_unmap(void *shared, unsigned long nr_gframes) +static void arch_gnttab_vfree(struct gnttab_vm_area *area) +{ + free_vm_area(area->area); + kfree(area->ptes); +} + +int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status) { - apply_to_page_range(&init_mm, (unsigned long)shared, - PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL); + int ret; + + if (!xen_pv_domain()) + return 0; + + ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared); + if (ret < 0) + return ret; + + /* + * Always allocate the space for the status frames in case + * we're migrated to a host with V2 support. + */ + ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status); + if (ret < 0) + goto err; + + return 0; + err: + arch_gnttab_vfree(&gnttab_shared_vm_area); + return -ENOMEM; } + #ifdef CONFIG_XEN_PVH #include #include -#include #include static int __init xlated_setup_gnttab_pages(void) { -- cgit v1.2.1 From 438b33c7145ca8a5131a30c36d8f59bce119a19a Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Wed, 2 Jul 2014 11:25:29 +0100 Subject: xen/grant-table: remove support for V2 tables Since 11c7ff17c9b6dbf3a4e4f36be30ad531a6cf0ec9 (xen/grant-table: Force to use v1 of grants.) the code for V2 grant tables is not used. Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/grant-table.c | 60 ++++------------------------------------------ 1 file changed, 5 insertions(+), 55 deletions(-) (limited to 'arch/x86/xen') diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c index ebfa9b2c871d..c0413046483a 100644 --- a/arch/x86/xen/grant-table.c +++ b/arch/x86/xen/grant-table.c @@ -49,7 +49,7 @@ static struct gnttab_vm_area { struct vm_struct *area; pte_t **ptes; -} gnttab_shared_vm_area, gnttab_status_vm_area; +} gnttab_shared_vm_area; int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, unsigned long max_nr_gframes, @@ -73,43 +73,16 @@ int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, return 0; } -int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, - unsigned long max_nr_gframes, - grant_status_t **__shared) -{ - grant_status_t *shared = *__shared; - unsigned long addr; - unsigned long i; - - if (shared == NULL) - *__shared = shared = gnttab_status_vm_area.area->addr; - - addr = (unsigned long)shared; - - for (i = 0; i < nr_gframes; i++) { - set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i], - mfn_pte(frames[i], PAGE_KERNEL)); - addr += PAGE_SIZE; - } - - return 0; -} - void arch_gnttab_unmap(void *shared, unsigned long nr_gframes) { - pte_t **ptes; unsigned long addr; unsigned long i; - if (shared == gnttab_status_vm_area.area->addr) - ptes = gnttab_status_vm_area.ptes; - else - ptes = gnttab_shared_vm_area.ptes; - addr = (unsigned long)shared; for (i = 0; i < nr_gframes; i++) { - set_pte_at(&init_mm, addr, ptes[i], __pte(0)); + set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i], + __pte(0)); addr += PAGE_SIZE; } } @@ -129,35 +102,12 @@ static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames) return 0; } -static void arch_gnttab_vfree(struct gnttab_vm_area *area) +int arch_gnttab_init(unsigned long nr_shared) { - free_vm_area(area->area); - kfree(area->ptes); -} - -int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status) -{ - int ret; - if (!xen_pv_domain()) return 0; - ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared); - if (ret < 0) - return ret; - - /* - * Always allocate the space for the status frames in case - * we're migrated to a host with V2 support. - */ - ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status); - if (ret < 0) - goto err; - - return 0; - err: - arch_gnttab_vfree(&gnttab_shared_vm_area); - return -ENOMEM; + return arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared); } #ifdef CONFIG_XEN_PVH -- cgit v1.2.1 From 3fbdf631b765571b18ee51e073d8f46958e98ceb Mon Sep 17 00:00:00 2001 From: Matt Rushton Date: Sat, 19 Jul 2014 17:01:34 -0700 Subject: xen/setup: Remove Identity Map Debug Message Removing a debug message for setting the identity map since it becomes rather noisy after rework of the identity map code. Signed-off-by: Matthew Rushton Signed-off-by: David Vrabel --- arch/x86/xen/p2m.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/x86/xen') diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 9bb3d82ffec8..3172692381ae 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -841,10 +841,9 @@ unsigned long __init set_phys_range_identity(unsigned long pfn_s, pfn = ALIGN(pfn, P2M_PER_PAGE); } - if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s), + WARN((pfn - pfn_s) != (pfn_e - pfn_s), "Identity mapping failed. We are %ld short of 1-1 mappings!\n", - (pfn_e - pfn_s) - (pfn - pfn_s))) - printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn); + (pfn_e - pfn_s) - (pfn - pfn_s)); return pfn - pfn_s; } -- cgit v1.2.1