* [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware [not found] ` <20080625005739.GM6938@duo.random> @ 2008-06-25 1:18 ` Andrea Arcangeli, Andrea Arcangeli 2008-07-29 12:11 ` Andrea Arcangeli, Andrea Arcangeli 0 siblings, 1 reply; 11+ messages in thread From: Andrea Arcangeli, Andrea Arcangeli @ 2008-06-25 1:18 UTC (permalink / raw) To: benami, Avi Kivity, Andrew Morton Cc: amit.shah, kvm, aliguori, allen.m.kay, muli, linux-mm This has to be applied to the host kernel and for example specifying a relocation address of 0x20000000 it will allow to start kvm guests capable of pci-passthrough up to "-m 512" by passing the "-reserved-ram" parameter in the command line. There's no risk of errors from the user thanks to the reserved ranges being provided to the virtualization software through /proc/iomem. Only you shouldn't run more than one -reserved-ram kvm quest per system at once. This works by reserving the ram early in the e820 map so the initial pagetables are allocated above the kernel .text relocation and then I make the sparse code think the reserved-ram is actually available (so struct pages are allocated) and finally I've to reserve those pages in the bootmem allocator immediately after the bootmem allocator has been initialized, so they remain PageReserved not used by linux, but with 'struct page' backing so they can still be exported to qemu via device driver vma->fault (as they can still be the target of any emulated dma, not all devices will passthrough). The virtualization software must create for the guest an e820 map that only includes the "reserved RAM" regions but if the guest touches memory with guest physical address in the "reserved RAM failed" ranges it should provide that as ram and map it with a non linear mapping (in practice the only problem is for the first page at address 0 physical which is usually the bios and no sane OS is doing DMA to it). vmx ~ # cat /proc/iomem |head -n 20 00000000-00000fff : reserved RAM failed 00001000-0008ffff : reserved RAM 00090000-00091fff : reserved RAM failed 00092000-0009cfff : reserved RAM 0009d000-0009ffff : reserved 000a0000-000ec16f : reserved RAM failed 000ec170-000fffff : reserved 00100000-1fffffff : reserved RAM 20000000-bff9ffff : System RAM 20000000-20315f65 : Kernel code 20315f66-204c3767 : Kernel data 20557000-205c9eff : Kernel bss bffa0000-bffaffff : ACPI Tables bffb0000-bffdffff : ACPI Non-volatile Storage bffe0000-bffedfff : reserved bfff0000-bfffffff : reserved d0000000-dfffffff : PCI Bus 0000:02 d0000000-dfffffff : 0000:02:00.0 e0000000-efffffff : PCI MMCONFIG 0 e0000000-efffffff : pnp 00:0c Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> --- diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1198,8 +1198,36 @@ config CRASH_DUMP (CONFIG_RELOCATABLE=y). For more details see Documentation/kdump/kdump.txt +config RESERVE_PHYSICAL_START + bool "Reserve all RAM below PHYSICAL_START (EXPERIMENTAL)" + depends on !RELOCATABLE && X86_64 + help + This makes the kernel use only RAM above __PHYSICAL_START. + All memory below __PHYSICAL_START will be left unused and + marked as "reserved RAM" in /proc/iomem. The few special + pages that can't be relocated at addresses above + __PHYSICAL_START and that can't be guaranteed to be unused + by the running kernel will be marked "reserved RAM failed" + in /proc/iomem. Those may or may be not used by the kernel + (for example SMP trampoline pages would only be used if + CPU hotplug is enabled). + + The "reserved RAM" can be mapped by virtualization software + with /dev/mem to create a 1:1 mapping between guest physical + (bus) address and host physical (bus) address. This will + allow PCI passthrough with DMA for the guest using the RAM + with the 1:1 mapping. The only detail to take care of is the + RAM marked "reserved RAM failed". The virtualization + software must create for the guest an e820 map that only + includes the "reserved RAM" regions but if the guest touches + memory with guest physical address in the "reserved RAM + failed" ranges (Linux guest will do that even if the RAM + isn't present in the e820 map), it should provide that as + RAM and map it with a non-linear mapping. This should allow + any Linux kernel to run fine and hopefully any other OS too. + config PHYSICAL_START - hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) + hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP || RESERVE_PHYSICAL_START) default "0x1000000" if X86_NUMAQ default "0x200000" if X86_64 default "0x100000" diff --git a/arch/x86/kernel/e820_64.c b/arch/x86/kernel/e820_64.c --- a/arch/x86/kernel/e820_64.c +++ b/arch/x86/kernel/e820_64.c @@ -119,7 +119,31 @@ void __init early_res_to_bootmem(unsigne printk(KERN_INFO " early res: %d [%lx-%lx] %s\n", i, final_start, final_end - 1, r->name); reserve_bootmem_generic(final_start, final_end - final_start); +#ifdef CONFIG_RESERVE_PHYSICAL_START + if (r->start < __PHYSICAL_START) + add_memory_region(r->start, r->end - r->start, + E820_RESERVED_RAM_FAILED); +#endif } +#ifdef CONFIG_RESERVE_PHYSICAL_START + /* solve E820_RESERVED_RAM vs E820_RESERVED_RAM_FAILED conflicts */ + update_e820(); + + /* now reserve E820_RESERVED_RAM */ + for (i = 0; i < e820.nr_map; i++) { + struct e820entry *ei = &e820.map[i]; + + if (ei->type != E820_RESERVED_RAM) + continue; + final_start = max(start, (unsigned long) ei->addr); + final_end = min(end, (unsigned long) (ei->addr + ei->size)); + if (final_start >= final_end) + continue; + reserve_bootmem_generic(final_start, final_end - final_start); + printk(KERN_INFO " bootmem reserved RAM: [%lx-%lx]\n", + final_start, final_end - 1); + } +#endif } /* Check for already reserved areas */ @@ -336,6 +360,16 @@ void __init e820_reserve_resources(void) case E820_RAM: res->name = "System RAM"; break; case E820_ACPI: res->name = "ACPI Tables"; break; case E820_NVS: res->name = "ACPI Non-volatile Storage"; break; +#ifdef CONFIG_RESERVE_PHYSICAL_START + case E820_RESERVED_RAM_FAILED: + res->name = "reserved RAM failed"; + break; + case E820_RESERVED_RAM: + memset(__va(e820.map[i].addr), + POISON_FREE_INITMEM, e820.map[i].size); + res->name = "reserved RAM"; + break; +#endif default: res->name = "reserved"; } res->start = e820.map[i].addr; @@ -377,6 +411,16 @@ void __init e820_mark_nosave_regions(voi } } +static int __init e820_is_not_ram(int type) +{ +#ifdef CONFIG_RESERVE_PHYSICAL_START + return type != E820_RAM && type != E820_RESERVED_RAM && + type != E820_RESERVED_RAM_FAILED; +#else + return type != E820_RAM; +#endif +} + /* * Finds an active region in the address range from start_pfn to end_pfn and * returns its range in ei_startpfn and ei_endpfn for the e820 entry. @@ -395,11 +439,11 @@ static int __init e820_find_active_regio return 0; /* Check if max_pfn_mapped should be updated */ - if (ei->type != E820_RAM && *ei_endpfn > max_pfn_mapped) + if (e820_is_not_ram(ei->type) && *ei_endpfn > max_pfn_mapped) max_pfn_mapped = *ei_endpfn; /* Skip if map is outside the node */ - if (ei->type != E820_RAM || *ei_endpfn <= start_pfn || + if (e820_is_not_ram(ei->type) || *ei_endpfn <= start_pfn || *ei_startpfn >= end_pfn) return 0; @@ -495,6 +539,14 @@ static void __init e820_print_map(char * case E820_NVS: printk(KERN_CONT "(ACPI NVS)\n"); break; +#ifdef CONFIG_RESERVE_PHYSICAL_START + case E820_RESERVED_RAM: + printk(KERN_CONT "(reserved RAM)\n"); + break; + case E820_RESERVED_RAM_FAILED: + printk(KERN_CONT "(reserved RAM failed)\n"); + break; +#endif default: printk(KERN_CONT "type %u\n", e820.map[i].type); break; @@ -724,9 +776,31 @@ static int __init copy_e820_map(struct e u64 end = start + size; u32 type = biosmap->type; +#ifdef CONFIG_RESERVE_PHYSICAL_START + /* make space for two more low-prio types */ + type += 2; +#endif + /* Overflow in 64 bits? Ignore the memory map. */ if (start > end) return -1; + +#ifdef CONFIG_RESERVE_PHYSICAL_START + if (type == E820_RAM) { + if (end <= __PHYSICAL_START) { + add_memory_region(start, size, + E820_RESERVED_RAM); + continue; + } + if (start < __PHYSICAL_START) { + add_memory_region(start, + __PHYSICAL_START-start, + E820_RESERVED_RAM); + size -= __PHYSICAL_START-start; + start = __PHYSICAL_START; + } + } +#endif add_memory_region(start, size, type); } while (biosmap++, --nr_map); diff --git a/include/asm-x86/e820.h b/include/asm-x86/e820.h --- a/include/asm-x86/e820.h +++ b/include/asm-x86/e820.h @@ -4,10 +4,19 @@ #define E820MAX 128 /* number of entries in E820MAP */ #define E820NR 0x1e8 /* # entries in E820MAP */ +#ifdef CONFIG_RESERVE_PHYSICAL_START +#define E820_RESERVED_RAM 1 +#define E820_RESERVED_RAM_FAILED 2 +#define E820_RAM 3 +#define E820_RESERVED 4 +#define E820_ACPI 5 +#define E820_NVS 6 +#else #define E820_RAM 1 #define E820_RESERVED 2 #define E820_ACPI 3 #define E820_NVS 4 +#endif #ifndef __ASSEMBLY__ struct e820entry { diff --git a/include/asm-x86/page_64.h b/include/asm-x86/page_64.h --- a/include/asm-x86/page_64.h +++ b/include/asm-x86/page_64.h @@ -29,6 +29,7 @@ #define __PAGE_OFFSET _AC(0xffff810000000000, UL) #define __PHYSICAL_START CONFIG_PHYSICAL_START +#define __PHYSICAL_OFFSET (__PHYSICAL_START-0x200000) #define __KERNEL_ALIGN 0x200000 /* @@ -51,7 +52,7 @@ * Kernel image size is limited to 512 MB (see level2_kernel_pgt in * arch/x86/kernel/head_64.S), and it is mapped here: */ -#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) +#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024 + __PHYSICAL_OFFSET) #define KERNEL_IMAGE_START _AC(0xffffffff80000000, UL) #ifndef __ASSEMBLY__ diff --git a/include/asm-x86/pgtable_64.h b/include/asm-x86/pgtable_64.h --- a/include/asm-x86/pgtable_64.h +++ b/include/asm-x86/pgtable_64.h @@ -145,7 +145,7 @@ static inline void native_pgd_clear(pgd_ #define VMALLOC_START _AC(0xffffc20000000000, UL) #define VMALLOC_END _AC(0xffffe1ffffffffff, UL) #define VMEMMAP_START _AC(0xffffe20000000000, UL) -#define MODULES_VADDR _AC(0xffffffffa0000000, UL) +#define MODULES_VADDR (0xffffffffa0000000UL+__PHYSICAL_OFFSET) #define MODULES_END _AC(0xfffffffffff00000, UL) #define MODULES_LEN (MODULES_END - MODULES_VADDR) diff --git a/include/asm-x86/trampoline.h b/include/asm-x86/trampoline.h --- a/include/asm-x86/trampoline.h +++ b/include/asm-x86/trampoline.h @@ -13,7 +13,11 @@ extern unsigned long init_rsp; extern unsigned long init_rsp; extern unsigned long initial_code; +#ifndef CONFIG_RESERVE_PHYSICAL_START #define TRAMPOLINE_BASE 0x6000 +#else +#define TRAMPOLINE_BASE 0x90000 /* move it next to 640k */ +#endif extern unsigned long setup_trampoline(void); #endif /* __ASSEMBLY__ */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-06-25 1:18 ` [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware Andrea Arcangeli, Andrea Arcangeli @ 2008-07-29 12:11 ` Andrea Arcangeli, Andrea Arcangeli 2008-07-29 12:43 ` Andi Kleen 0 siblings, 1 reply; 11+ messages in thread From: Andrea Arcangeli, Andrea Arcangeli @ 2008-07-29 12:11 UTC (permalink / raw) To: benami, Avi Kivity, Andrew Morton Cc: amit.shah, kvm, aliguori, allen.m.kay, muli, linux-mm, andi, tglx, mingo The "reserved RAM" can be mapped by virtualization software with /dev/mem to create a 1:1 mapping between guest physical (bus) address and host physical (bus) address. This will allow pci passthrough with DMA for the guest using the ram with the 1:1 mapping. The only detail to take care of is the ram marked "reserved RAM failed". The virtualization software must create for the guest an e820 map that only includes the "reserved RAM" regions but if the guest touches memory with guest physical address in the "reserved RAM failed" ranges (linux guest will do that even if the ram isn't present in the e820 map), it should provide that as ram and map it with a non linear mapping. This should allow any linux kernel to run fine and hopefully any other OS too. svm ~ # cat /proc/iomem |head -n 20 00000000-00000fff : reserved RAM failed 00001000-00005fff : reserved RAM 00006000-00007fff : reserved RAM failed 00008000-0009efff : reserved RAM 0009f000-0009ffff : reserved 000cd600-000cffff : pnp 00:0d 000f0000-000fffff : reserved 00100000-0fffffff : reserved RAM 10000000-3dedffff : System RAM 10000000-10329ab2 : Kernel code 10329ab3-104933e7 : Kernel data 104f5000-10558e67 : Kernel bss 3dee0000-3dee2fff : ACPI Non-volatile Storage 3dee3000-3deeffff : ACPI Tables 3def0000-3defffff : reserved 3dff0000-3ffeffff : pnp 00:0d e0000000-efffffff : reserved fa000000-fbffffff : PCI Bus #01 fa000000-fbffffff : 0000:01:05.0 fda00000-fdbfffff : PCI Bus #01 svm ~ # hexdump /dev/mem | grep -C2 'cccc cccc cccc cccc' 00007e0 0000 0000 0000 0000 0000 0000 0000 0000 * 0001000 cccc cccc cccc cccc cccc cccc cccc cccc * 0006000 a5a5 a5a5 8ec8 8ed8 8ec0 66d0 06c7 0000 -- * 0007ff0 0000 0000 0000 0000 3063 1000 0000 0000 0008000 cccc cccc cccc cccc cccc cccc cccc cccc * 009f000 0002 0000 0000 0000 0000 0000 0000 0000 -- 00fffe0 6000 3c03 45e7 0184 0500 0082 01c0 0223 00ffff0 5bea 00e0 31f0 2f32 3931 302f 0037 12fc 0100000 cccc cccc cccc cccc cccc cccc cccc cccc * 10000000 8d48 f92d ffff 48ff ed81 0000 1000 8948 ^C svm ~ # Signed-off-by: Andrea Arcangeli <andrea@qumranet.com> --- This is a port to current linux-2.6.git of the previous reserved-ram patch. Let me know if there's a chance to get this acked and included. Anything that isn't at compile time would require much bigger changes just to parse the command line at 16bit realmode time to know where to relocate the kernel dynamically. Because 1:1 is a corner case feature required only by some users, this is the minimal intrusive approach. This also has some limits as it can't reserve more than 1g, and with a few more changes 2g but this is ok for a long time as the virtualized 1:1 guest doesn't need to be huge, just a desktop. diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1276,8 +1276,36 @@ config CRASH_DUMP (CONFIG_RELOCATABLE=y). For more details see Documentation/kdump/kdump.txt +config RESERVE_PHYSICAL_START + bool "Reserve all RAM below PHYSICAL_START (EXPERIMENTAL)" + depends on !RELOCATABLE && X86_64 + help + This makes the kernel use only RAM above __PHYSICAL_START. + All memory below __PHYSICAL_START will be left unused and + marked as "reserved RAM" in /proc/iomem. The few special + pages that can't be relocated at addresses above + __PHYSICAL_START and that can't be guaranteed to be unused + by the running kernel will be marked "reserved RAM failed" + in /proc/iomem. Those may or may be not used by the kernel + (for example SMP trampoline pages would only be used if + CPU hotplug is enabled). + + The "reserved RAM" can be mapped by virtualization software + with /dev/mem to create a 1:1 mapping between guest physical + (bus) address and host physical (bus) address. This will + allow PCI passthrough with DMA for the guest using the RAM + with the 1:1 mapping. The only detail to take care of is the + RAM marked "reserved RAM failed". The virtualization + software must create for the guest an e820 map that only + includes the "reserved RAM" regions but if the guest touches + memory with guest physical address in the "reserved RAM + failed" ranges (Linux guest will do that even if the RAM + isn't present in the e820 map), it should provide that as + RAM and map it with a non-linear mapping. This should allow + any Linux kernel to run fine and hopefully any other OS too. + config PHYSICAL_START - hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) + hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP || RESERVE_PHYSICAL_START) default "0x1000000" if X86_NUMAQ default "0x200000" if X86_64 default "0x100000" diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -148,6 +148,14 @@ void __init e820_print_map(char *who) case E820_NVS: printk(KERN_CONT "(ACPI NVS)\n"); break; +#ifdef CONFIG_RESERVE_PHYSICAL_START + case E820_RESERVED_RAM: + printk(KERN_CONT "(reserved RAM)\n"); + break; + case E820_RESERVED_RAM_FAILED: + printk(KERN_CONT "(reserved RAM failed)\n"); + break; +#endif default: printk(KERN_CONT "type %u\n", e820.map[i].type); break; @@ -384,10 +392,28 @@ static int __init __append_e820_map(stru u64 end = start + size; u32 type = biosmap->type; +#ifdef CONFIG_RESERVE_PHYSICAL_START + /* make space for two more low-prio types */ + type += 2; +#endif + /* Overflow in 64 bits? Ignore the memory map. */ if (start > end) return -1; +#ifdef CONFIG_RESERVE_PHYSICAL_START + if (type == E820_RAM) { + if (end <= __PHYSICAL_START) + type = E820_RESERVED_RAM; + else if (start < __PHYSICAL_START) { + e820_add_region(start, + __PHYSICAL_START-start, + E820_RESERVED_RAM); + size -= __PHYSICAL_START-start; + start = __PHYSICAL_START; + } + } +#endif e820_add_region(start, size, type); biosmap++; @@ -893,7 +919,35 @@ void __init early_res_to_bootmem(u64 sta final_start, final_end); reserve_bootmem_generic(final_start, final_end - final_start, BOOTMEM_DEFAULT); +#ifdef CONFIG_RESERVE_PHYSICAL_START + if (r->start < __PHYSICAL_START) + e820_add_region(r->start, r->end - r->start, + E820_RESERVED_RAM_FAILED); +#endif } +#ifdef CONFIG_RESERVE_PHYSICAL_START + /* solve E820_RESERVED_RAM vs E820_RESERVED_RAM_FAILED conflicts */ + update_e820(); + + /* now reserve E820_RESERVED_RAM */ + for (i = 0; i < e820.nr_map; i++) { + struct e820entry *ei = &e820.map[i]; + + if (ei->type != E820_RESERVED_RAM) + continue; + final_start = max(start, (u64) ei->addr); + final_end = min(end, (u64) (ei->addr + ei->size)); + if (final_start >= final_end) + continue; + if (reserve_bootmem_generic(final_start, + final_end - final_start, + BOOTMEM_DEFAULT)) + printk(KERN_ERR "reserved physical start failure"); + else + printk(KERN_INFO " bootmem reserved RAM: [%Lx-%Lx]\n", + final_start, final_end - 1); + } +#endif } /* Check for already reserved areas */ @@ -1095,6 +1149,17 @@ unsigned long __init e820_end_of_low_ram { return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM); } + +static int __init e820_is_not_ram(int type) +{ +#ifdef CONFIG_RESERVE_PHYSICAL_START + return type != E820_RAM && type != E820_RESERVED_RAM && + type != E820_RESERVED_RAM_FAILED; +#else + return type != E820_RAM; +#endif +} + /* * Finds an active region in the address range from start_pfn to last_pfn and * returns its range in ei_startpfn and ei_endpfn for the e820 entry. @@ -1115,8 +1180,8 @@ int __init e820_find_active_region(const return 0; /* Skip if map is outside the node */ - if (ei->type != E820_RAM || *ei_endpfn <= start_pfn || - *ei_startpfn >= last_pfn) + if (e820_is_not_ram(ei->type) || *ei_endpfn <= start_pfn || + *ei_startpfn >= last_pfn) return 0; /* Check for overlaps */ @@ -1260,6 +1325,10 @@ static inline const char *e820_type_to_s case E820_RAM: return "System RAM"; case E820_ACPI: return "ACPI Tables"; case E820_NVS: return "ACPI Non-volatile Storage"; +#ifdef CONFIG_RESERVE_PHYSICAL_START + case E820_RESERVED_RAM_FAILED: return "reserved RAM failed"; + case E820_RESERVED_RAM: return "reserved RAM"; +#endif default: return "reserved"; } } @@ -1289,6 +1358,12 @@ void __init e820_reserve_resources(void) res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; insert_resource(&iomem_resource, res); res++; + +#ifdef CONFIG_RESERVE_PHYSICAL_START + if (i == E820_RESERVED_RAM) + memset(__va(e820.map[i].addr), + POISON_FREE_INITMEM, e820.map[i].size); +#endif } for (i = 0; i < e820_saved.nr_map; i++) { diff --git a/include/asm-x86/e820.h b/include/asm-x86/e820.h --- a/include/asm-x86/e820.h +++ b/include/asm-x86/e820.h @@ -39,10 +39,19 @@ #define E820NR 0x1e8 /* # entries in E820MAP */ +#ifdef CONFIG_RESERVE_PHYSICAL_START +#define E820_RESERVED_RAM 1 +#define E820_RESERVED_RAM_FAILED 2 +#define E820_RAM 3 +#define E820_RESERVED 4 +#define E820_ACPI 5 +#define E820_NVS 6 +#else #define E820_RAM 1 #define E820_RESERVED 2 #define E820_ACPI 3 #define E820_NVS 4 +#endif /* reserved RAM used by kernel itself */ #define E820_RESERVED_KERN 128 diff --git a/include/asm-x86/page_64.h b/include/asm-x86/page_64.h --- a/include/asm-x86/page_64.h +++ b/include/asm-x86/page_64.h @@ -35,6 +35,7 @@ #define __PAGE_OFFSET _AC(0xffff880000000000, UL) #define __PHYSICAL_START CONFIG_PHYSICAL_START +#define __PHYSICAL_OFFSET (__PHYSICAL_START-0x200000) #define __KERNEL_ALIGN 0x200000 /* @@ -57,7 +58,7 @@ * Kernel image size is limited to 512 MB (see level2_kernel_pgt in * arch/x86/kernel/head_64.S), and it is mapped here: */ -#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) +#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024 + __PHYSICAL_OFFSET) #define KERNEL_IMAGE_START _AC(0xffffffff80000000, UL) #ifndef __ASSEMBLY__ diff --git a/include/asm-x86/pgtable_64.h b/include/asm-x86/pgtable_64.h --- a/include/asm-x86/pgtable_64.h +++ b/include/asm-x86/pgtable_64.h @@ -150,7 +150,7 @@ static inline void native_pgd_clear(pgd_ #define VMALLOC_START _AC(0xffffc20000000000, UL) #define VMALLOC_END _AC(0xffffe1ffffffffff, UL) #define VMEMMAP_START _AC(0xffffe20000000000, UL) -#define MODULES_VADDR _AC(0xffffffffa0000000, UL) +#define MODULES_VADDR (0xffffffffa0000000UL+__PHYSICAL_OFFSET) #define MODULES_END _AC(0xfffffffffff00000, UL) #define MODULES_LEN (MODULES_END - MODULES_VADDR) diff --git a/include/asm-x86/trampoline.h b/include/asm-x86/trampoline.h --- a/include/asm-x86/trampoline.h +++ b/include/asm-x86/trampoline.h @@ -13,7 +13,11 @@ extern unsigned long init_rsp; extern unsigned long init_rsp; extern unsigned long initial_code; +#ifndef CONFIG_RESERVE_PHYSICAL_START #define TRAMPOLINE_BASE 0x6000 +#else +#define TRAMPOLINE_BASE 0x90000 /* move it next to 640k */ +#endif extern unsigned long setup_trampoline(void); #endif /* __ASSEMBLY__ */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-29 12:11 ` Andrea Arcangeli, Andrea Arcangeli @ 2008-07-29 12:43 ` Andi Kleen 2008-07-29 12:53 ` Andrea Arcangeli 0 siblings, 1 reply; 11+ messages in thread From: Andi Kleen @ 2008-07-29 12:43 UTC (permalink / raw) To: Andrea Arcangeli Cc: benami, Avi Kivity, Andrew Morton, amit.shah, kvm, aliguori, allen.m.kay, muli, linux-mm, andi, tglx, mingo > This is a port to current linux-2.6.git of the previous reserved-ram > patch. Let me know if there's a chance to get this acked and > included. Anything that isn't at compile time would require much I still think runtime would be far better. Nobody really wants a proliferation of more weird special kernel images. > bigger changes just to parse the command line at 16bit realmode time You could always do it with kexec if you think 16bit real mode is too hard. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-29 12:43 ` Andi Kleen @ 2008-07-29 12:53 ` Andrea Arcangeli 2008-07-29 13:17 ` Andi Kleen 0 siblings, 1 reply; 11+ messages in thread From: Andrea Arcangeli @ 2008-07-29 12:53 UTC (permalink / raw) To: Andi Kleen Cc: benami, Avi Kivity, Andrew Morton, amit.shah, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo On Tue, Jul 29, 2008 at 02:43:17PM +0200, Andi Kleen wrote: > > This is a port to current linux-2.6.git of the previous reserved-ram > > patch. Let me know if there's a chance to get this acked and > > included. Anything that isn't at compile time would require much > > I still think runtime would be far better. Nobody really wants > a proliferation of more weird special kernel images. Not for the usage we're interested about but surely this would prevent distro to take advantage of the feature. The question is if distro need to take advantage of the feature in the first place instead of sticking with VT-d. 1:1 isn't secure virtualization as the guest must be trusted so it's not necessarily a good model to deploy to users that don't know exactly what they're doing. > > bigger changes just to parse the command line at 16bit realmode time > > You could always do it with kexec if you think 16bit real mode is > too hard. It's not too hard, but it'll add bloat to the 16 bit part of the boot in the bzImage. It's likely simpler than kexec and surely more user-friendly to setup for the end user. In any case, my patch does the needed bits with regard to the e820 map. An incremental patch can add the parsing of the booatloader and switch the Kconfig dependency from PHYSICAL_START to RELOCATABLE. The e820 file will then have to replace the __PHYSICAL_START define with something else and that's all. I mean it's not entirely backwards to provide a compile time smaller and simpler approach initially, and then to go where you want to go incrementally later if we're sure there's enough userbase needing 1:1. I'm not so interested to go there right now, because while this code is useful right now because the majority of systems out there lacks VT-d/iommu, I suspect this code could be nuked in the long run when all systems will ship with that, which is why I kept it all under #ifdef, and the changes to the other files outside ifdef are bugfixes needed if you want to kexec-relocate above 40m or so that should be kept. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-29 12:53 ` Andrea Arcangeli @ 2008-07-29 13:17 ` Andi Kleen 2008-07-30 6:20 ` Amit Shah 0 siblings, 1 reply; 11+ messages in thread From: Andi Kleen @ 2008-07-29 13:17 UTC (permalink / raw) To: Andrea Arcangeli Cc: Andi Kleen, benami, Avi Kivity, Andrew Morton, amit.shah, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo > I'm not so interested to go there right now, because while this code > is useful right now because the majority of systems out there lacks > VT-d/iommu, I suspect this code could be nuked in the long > run when all systems will ship with that, which is why I kept it all Actually at least on Intel platforms and if you exclude the lowest end VT-d is shipping universally for quite some time now. If you buy a Intel box today or bought it in the last year the chances are pretty high that it has VT-d support. > under #ifdef, and the changes to the other files outside ifdef are > bugfixes needed if you want to kexec-relocate above 40m or so that > should be kept. You should split that out then into a separate patch. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-29 13:17 ` Andi Kleen @ 2008-07-30 6:20 ` Amit Shah 2008-07-30 12:27 ` Andi Kleen 2008-07-30 13:58 ` Andrea Arcangeli 0 siblings, 2 replies; 11+ messages in thread From: Amit Shah @ 2008-07-30 6:20 UTC (permalink / raw) To: Andi Kleen Cc: Andrea Arcangeli, benami, Avi Kivity, Andrew Morton, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo * On Tuesday 29 July 2008 18:47:35 Andi Kleen wrote: > > I'm not so interested to go there right now, because while this code > > is useful right now because the majority of systems out there lacks > > VT-d/iommu, I suspect this code could be nuked in the long > > run when all systems will ship with that, which is why I kept it all > > Actually at least on Intel platforms and if you exclude the lowest end > VT-d is shipping universally for quite some time now. If you > buy a Intel box today or bought it in the last year the chances are pretty > high that it has VT-d support. I think you mean VT-x, which is virtualization extensions for the x86 architecture. VT-d is virtualization extensions for devices (IOMMU). Amit -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-30 6:20 ` Amit Shah @ 2008-07-30 12:27 ` Andi Kleen 2008-07-30 13:58 ` Andrea Arcangeli 1 sibling, 0 replies; 11+ messages in thread From: Andi Kleen @ 2008-07-30 12:27 UTC (permalink / raw) To: Amit Shah Cc: Andi Kleen, Andrea Arcangeli, benami, Avi Kivity, Andrew Morton, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo On Wed, Jul 30, 2008 at 11:50:43AM +0530, Amit Shah wrote: > * On Tuesday 29 July 2008 18:47:35 Andi Kleen wrote: > > > I'm not so interested to go there right now, because while this code > > > is useful right now because the majority of systems out there lacks > > > VT-d/iommu, I suspect this code could be nuked in the long > > > run when all systems will ship with that, which is why I kept it all > > > > Actually at least on Intel platforms and if you exclude the lowest end > > VT-d is shipping universally for quite some time now. If you > > buy a Intel box today or bought it in the last year the chances are pretty > > high that it has VT-d support. > > I think you mean VT-x, which is virtualization extensions for the x86 > architecture. VT-d is virtualization extensions for devices (IOMMU). No I really mean VT-d. The modern not very lowend Intel IOHubs all have it. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-30 6:20 ` Amit Shah 2008-07-30 12:27 ` Andi Kleen @ 2008-07-30 13:58 ` Andrea Arcangeli 2008-07-30 14:16 ` Dor Laor 2008-07-30 14:22 ` FUJITA Tomonori 1 sibling, 2 replies; 11+ messages in thread From: Andrea Arcangeli @ 2008-07-30 13:58 UTC (permalink / raw) To: Amit Shah Cc: Andi Kleen, benami, Avi Kivity, Andrew Morton, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo On Wed, Jul 30, 2008 at 11:50:43AM +0530, Amit Shah wrote: > * On Tuesday 29 July 2008 18:47:35 Andi Kleen wrote: > > > I'm not so interested to go there right now, because while this code > > > is useful right now because the majority of systems out there lacks > > > VT-d/iommu, I suspect this code could be nuked in the long > > > run when all systems will ship with that, which is why I kept it all > > > > Actually at least on Intel platforms and if you exclude the lowest end > > VT-d is shipping universally for quite some time now. If you > > buy a Intel box today or bought it in the last year the chances are pretty > > high that it has VT-d support. > > I think you mean VT-x, which is virtualization extensions for the x86 > architecture. VT-d is virtualization extensions for devices (IOMMU). I think Andi understood VT-d right but even if he was right that every reader of this email that is buying a new VT-x system today is also almost guaranteed to get a VT-d motherboard (which I disagree unless you buy some really expensive toy), there are current large installations of VT-x systems that lacks VT-d and that with recent current dual/quadcore cpus are very fast and will be used for the next couple of years and they will not upgrade just the motherboard to use pci-passthrough. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-30 13:58 ` Andrea Arcangeli @ 2008-07-30 14:16 ` Dor Laor 2008-07-30 14:38 ` Andrea Arcangeli 2008-07-30 14:22 ` FUJITA Tomonori 1 sibling, 1 reply; 11+ messages in thread From: Dor Laor @ 2008-07-30 14:16 UTC (permalink / raw) To: Andrea Arcangeli Cc: Amit Shah, Andi Kleen, benami, Avi Kivity, Andrew Morton, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo Andrea Arcangeli wrote: > On Wed, Jul 30, 2008 at 11:50:43AM +0530, Amit Shah wrote: > >> * On Tuesday 29 July 2008 18:47:35 Andi Kleen wrote: >> >>>> I'm not so interested to go there right now, because while this code >>>> is useful right now because the majority of systems out there lacks >>>> VT-d/iommu, I suspect this code could be nuked in the long >>>> run when all systems will ship with that, which is why I kept it all >>>> >>> Actually at least on Intel platforms and if you exclude the lowest end >>> VT-d is shipping universally for quite some time now. If you >>> buy a Intel box today or bought it in the last year the chances are pretty >>> high that it has VT-d support. >>> >> I think you mean VT-x, which is virtualization extensions for the x86 >> architecture. VT-d is virtualization extensions for devices (IOMMU). >> > > I think Andi understood VT-d right but even if he was right that every > reader of this email that is buying a new VT-x system today is also > almost guaranteed to get a VT-d motherboard (which I disagree unless > you buy some really expensive toy), there are current large > installations of VT-x systems that lacks VT-d and that with recent > current dual/quadcore cpus are very fast and will be used for the next > couple of years and they will not upgrade just the motherboard to use > pci-passthrough. > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > In addition KVM is used in embedded too and things are slower there, we know of a specific use case (production) that demands 1:1 mapping and can't use VT-d -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-30 14:16 ` Dor Laor @ 2008-07-30 14:38 ` Andrea Arcangeli 0 siblings, 0 replies; 11+ messages in thread From: Andrea Arcangeli @ 2008-07-30 14:38 UTC (permalink / raw) To: Dor Laor Cc: Amit Shah, Andi Kleen, benami, Avi Kivity, Andrew Morton, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo On Wed, Jul 30, 2008 at 05:16:06PM +0300, Dor Laor wrote: > In addition KVM is used in embedded too and things are slower there, we > know of a specific use case (production) that demands > 1:1 mapping and can't use VT-d Since you mentioned this ;), I take opportunity to add that those embedded usages are the ones that are totally fine with the compile time passthrough-guest-ram decision, instead of a boot time decision. Those host kernels will likely have RT patches (KVM works great with preempt-RT indeed) and in turn the compile time ram selection is the least of their problems as you can imagine ;). So you can see my patch as an embedded-build option, similar to "Configure standard kernel features (for small systems)" and no distro is shipping new kernels with that feature on either. Than if we decide 1:1 should have larger userbase instead of only the people that knows what they're doing (i.e. 1:1 guest can destroy linux-hypervisor) we can always add a bit of strtol parsing to 16bit kernelloader. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware 2008-07-30 13:58 ` Andrea Arcangeli 2008-07-30 14:16 ` Dor Laor @ 2008-07-30 14:22 ` FUJITA Tomonori 1 sibling, 0 replies; 11+ messages in thread From: FUJITA Tomonori @ 2008-07-30 14:22 UTC (permalink / raw) To: andrea Cc: amit.shah, andi, benami, avi, akpm, kvm, aliguori, allen.m.kay, muli, linux-mm, tglx, mingo On Wed, 30 Jul 2008 15:58:46 +0200 Andrea Arcangeli <andrea@qumranet.com> wrote: > On Wed, Jul 30, 2008 at 11:50:43AM +0530, Amit Shah wrote: > > * On Tuesday 29 July 2008 18:47:35 Andi Kleen wrote: > > > > I'm not so interested to go there right now, because while this code > > > > is useful right now because the majority of systems out there lacks > > > > VT-d/iommu, I suspect this code could be nuked in the long > > > > run when all systems will ship with that, which is why I kept it all > > > > > > Actually at least on Intel platforms and if you exclude the lowest end > > > VT-d is shipping universally for quite some time now. If you > > > buy a Intel box today or bought it in the last year the chances are pretty > > > high that it has VT-d support. > > > > I think you mean VT-x, which is virtualization extensions for the x86 > > architecture. VT-d is virtualization extensions for devices (IOMMU). > > I think Andi understood VT-d right but even if he was right that every > reader of this email that is buying a new VT-x system today is also > almost guaranteed to get a VT-d motherboard (which I disagree unless > you buy some really expensive toy), there are current large > installations of VT-x systems that lacks VT-d and that with recent > current dual/quadcore cpus are very fast and will be used for the next > couple of years and they will not upgrade just the motherboard to use > pci-passthrough. Today, very inexpensive desktops (for example, Dell OptiPlex 755) have VT-d support. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2008-07-30 14:38 UTC | newest]
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2008-06-25 1:18 ` [PATCH] reserved-ram for pci-passthrough without VT-d capable hardware Andrea Arcangeli, Andrea Arcangeli
2008-07-29 12:11 ` Andrea Arcangeli, Andrea Arcangeli
2008-07-29 12:43 ` Andi Kleen
2008-07-29 12:53 ` Andrea Arcangeli
2008-07-29 13:17 ` Andi Kleen
2008-07-30 6:20 ` Amit Shah
2008-07-30 12:27 ` Andi Kleen
2008-07-30 13:58 ` Andrea Arcangeli
2008-07-30 14:16 ` Dor Laor
2008-07-30 14:38 ` Andrea Arcangeli
2008-07-30 14:22 ` FUJITA Tomonori
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