[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen/arm: add Persistent Map (PMAP) infrastructure
commit 4f17357b52f6ea9e76ff2375a6c61e8f43f65723 Author: Wei Liu <wei.liu2@xxxxxxxxxx> AuthorDate: Sat Jun 11 12:20:33 2022 +0100 Commit: Julien Grall <julien@xxxxxxx> CommitDate: Sat Jun 11 12:29:06 2022 +0100 xen/arm: add Persistent Map (PMAP) infrastructure The basic idea is like Persistent Kernel Map (PKMAP) in Linux. We pre-populate all the relevant page tables before the system is fully set up. We will need it on Arm in order to rework the arm64 version of xenheap_setup_mappings() as we may need to use pages allocated from the boot allocator before they are effectively mapped. This infrastructure is not lock-protected therefore can only be used before smpboot. After smpboot, map_domain_page() has to be used. This is based on the x86 version [1] that was originally implemented by Wei Liu. The PMAP infrastructure is implemented in common code with some arch helpers to set/clear the page-table entries and convertion between a fixmap slot to a virtual address... As mfn_to_xen_entry() now needs to be exported, take the opportunity to swich the parameter attr from unsigned to unsigned int. [1] <e92da4ad6015b6089737fcccba3ec1d6424649a5.1588278317.git.hongyxia@xxxxxxxxxx> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx> Signed-off-by: Hongyan Xia <hongyxia@xxxxxxxxxx> [julien: Adapted for Arm] Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx> Tested-by: Luca Fancellu <luca.fancellu@xxxxxxx> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> --- xen/arch/arm/Kconfig | 1 + xen/arch/arm/include/asm/fixmap.h | 24 +++++++++++++ xen/arch/arm/include/asm/lpae.h | 8 +++++ xen/arch/arm/include/asm/pmap.h | 29 ++++++++++++++++ xen/arch/arm/mm.c | 7 +--- xen/common/Kconfig | 3 ++ xen/common/Makefile | 1 + xen/common/pmap.c | 72 +++++++++++++++++++++++++++++++++++++++ xen/include/xen/pmap.h | 16 +++++++++ 9 files changed, 155 insertions(+), 6 deletions(-) diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index ecfa6822e4..a89a67802a 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -14,6 +14,7 @@ config ARM select HAS_DEVICE_TREE select HAS_PASSTHROUGH select HAS_PDX + select HAS_PMAP select IOMMU_FORCE_PT_SHARE config ARCH_DEFCONFIG diff --git a/xen/arch/arm/include/asm/fixmap.h b/xen/arch/arm/include/asm/fixmap.h index 1cee51e52a..365a2385a0 100644 --- a/xen/arch/arm/include/asm/fixmap.h +++ b/xen/arch/arm/include/asm/fixmap.h @@ -5,20 +5,44 @@ #define __ASM_FIXMAP_H #include <xen/acpi.h> +#include <xen/pmap.h> /* Fixmap slots */ #define FIXMAP_CONSOLE 0 /* The primary UART */ #define FIXMAP_MISC 1 /* Ephemeral mappings of hardware */ #define FIXMAP_ACPI_BEGIN 2 /* Start mappings of ACPI tables */ #define FIXMAP_ACPI_END (FIXMAP_ACPI_BEGIN + NUM_FIXMAP_ACPI_PAGES - 1) /* End mappings of ACPI tables */ +#define FIXMAP_PMAP_BEGIN (FIXMAP_ACPI_END + 1) /* Start of PMAP */ +#define FIXMAP_PMAP_END (FIXMAP_PMAP_BEGIN + NUM_FIX_PMAP - 1) /* End of PMAP */ + +#define FIXMAP_LAST FIXMAP_PMAP_END + +#define FIXADDR_START FIXMAP_ADDR(0) +#define FIXADDR_TOP FIXMAP_ADDR(FIXMAP_LAST) #ifndef __ASSEMBLY__ +/* + * Direct access to xen_fixmap[] should only happen when {set, + * clear}_fixmap() is unusable (e.g. where we would end up to + * recursively call the helpers). + */ +extern lpae_t xen_fixmap[XEN_PT_LPAE_ENTRIES]; + /* Map a page in a fixmap entry */ extern void set_fixmap(unsigned map, mfn_t mfn, unsigned attributes); /* Remove a mapping from a fixmap entry */ extern void clear_fixmap(unsigned map); +#define fix_to_virt(slot) ((void *)FIXMAP_ADDR(slot)) + +static inline unsigned int virt_to_fix(vaddr_t vaddr) +{ + BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); + + return ((vaddr - FIXADDR_START) >> PAGE_SHIFT); +} + #endif /* __ASSEMBLY__ */ #endif /* __ASM_FIXMAP_H */ diff --git a/xen/arch/arm/include/asm/lpae.h b/xen/arch/arm/include/asm/lpae.h index aecb320dec..fc19cbd847 100644 --- a/xen/arch/arm/include/asm/lpae.h +++ b/xen/arch/arm/include/asm/lpae.h @@ -4,6 +4,7 @@ #ifndef __ASSEMBLY__ #include <xen/page-defs.h> +#include <xen/mm-frame.h> /* * WARNING! Unlike the x86 pagetable code, where l1 is the lowest level and @@ -168,6 +169,13 @@ static inline bool lpae_is_superpage(lpae_t pte, unsigned int level) third_table_offset(addr) \ } +/* + * Standard entry type that we'll use to build Xen's own pagetables. + * We put the same permissions at every level, because they're ignored + * by the walker in non-leaf entries. + */ +lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned int attr); + #endif /* __ASSEMBLY__ */ /* diff --git a/xen/arch/arm/include/asm/pmap.h b/xen/arch/arm/include/asm/pmap.h new file mode 100644 index 0000000000..e094d13dd2 --- /dev/null +++ b/xen/arch/arm/include/asm/pmap.h @@ -0,0 +1,29 @@ +#ifndef __ASM_PMAP_H__ +#define __ASM_PMAP_H__ + +#include <xen/mm.h> + +#include <asm/fixmap.h> + +static inline void arch_pmap_map(unsigned int slot, mfn_t mfn) +{ + lpae_t *entry = &xen_fixmap[slot]; + lpae_t pte; + + ASSERT(!lpae_is_valid(*entry)); + + pte = mfn_to_xen_entry(mfn, PAGE_HYPERVISOR_RW); + pte.pt.table = 1; + write_pte(entry, pte); +} + +static inline void arch_pmap_unmap(unsigned int slot) +{ + lpae_t pte = {}; + + write_pte(&xen_fixmap[slot], pte); + + flush_xen_tlb_range_va_local(FIXMAP_ADDR(slot), PAGE_SIZE); +} + +#endif /* __ASM_PMAP_H__ */ diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 52b2a03940..bd1348a997 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -305,12 +305,7 @@ void dump_hyp_walk(vaddr_t addr) dump_pt_walk(ttbr, addr, HYP_PT_ROOT_LEVEL, 1); } -/* - * Standard entry type that we'll use to build Xen's own pagetables. - * We put the same permissions at every level, because they're ignored - * by the walker in non-leaf entries. - */ -static inline lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned attr) +lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned int attr) { lpae_t e = (lpae_t) { .pt = { diff --git a/xen/common/Kconfig b/xen/common/Kconfig index d921c74d61..5b6b2406c0 100644 --- a/xen/common/Kconfig +++ b/xen/common/Kconfig @@ -49,6 +49,9 @@ config HAS_KEXEC config HAS_PDX bool +config HAS_PMAP + bool + config HAS_SCHED_GRANULARITY bool diff --git a/xen/common/Makefile b/xen/common/Makefile index b1e076c30b..3baf83d527 100644 --- a/xen/common/Makefile +++ b/xen/common/Makefile @@ -29,6 +29,7 @@ obj-y += notifier.o obj-y += page_alloc.o obj-$(CONFIG_HAS_PDX) += pdx.o obj-$(CONFIG_PERF_COUNTERS) += perfc.o +obj-bin-$(CONFIG_HAS_PMAP) += pmap.init.o obj-y += preempt.o obj-y += random.o obj-y += rangeset.o diff --git a/xen/common/pmap.c b/xen/common/pmap.c new file mode 100644 index 0000000000..14517198aa --- /dev/null +++ b/xen/common/pmap.c @@ -0,0 +1,72 @@ +#include <xen/bitops.h> +#include <xen/init.h> +#include <xen/irq.h> +#include <xen/pmap.h> + +#include <asm/pmap.h> +#include <asm/fixmap.h> + +/* + * Simple mapping infrastructure to map / unmap pages in fixed map. + * This is used to set the page table before the map domain page infrastructure + * is initialized. + * + * This structure is not protected by any locks, so it must not be used after + * smp bring-up. + */ + +/* Bitmap to track which slot is used */ +static __initdata DECLARE_BITMAP(inuse, NUM_FIX_PMAP); + +void *__init pmap_map(mfn_t mfn) +{ + unsigned int idx; + unsigned int slot; + + ASSERT(system_state < SYS_STATE_smp_boot); + ASSERT(!in_irq()); + + idx = find_first_zero_bit(inuse, NUM_FIX_PMAP); + if ( idx == NUM_FIX_PMAP ) + panic("Out of PMAP slots\n"); + + __set_bit(idx, inuse); + + slot = idx + FIXMAP_PMAP_BEGIN; + ASSERT(slot >= FIXMAP_PMAP_BEGIN && slot <= FIXMAP_PMAP_END); + + /* + * We cannot use set_fixmap() here. We use PMAP when the domain map + * page infrastructure is not yet initialized, so map_pages_to_xen() called + * by set_fixmap() needs to map pages on demand, which then calls pmap() + * again, resulting in a loop. Modify the PTEs directly instead. The same + * is true for pmap_unmap(). + */ + arch_pmap_map(slot, mfn); + + return fix_to_virt(slot); +} + +void __init pmap_unmap(const void *p) +{ + unsigned int idx; + unsigned int slot = virt_to_fix((unsigned long)p); + + ASSERT(system_state < SYS_STATE_smp_boot); + ASSERT(slot >= FIXMAP_PMAP_BEGIN && slot <= FIXMAP_PMAP_END); + ASSERT(!in_irq()); + + idx = slot - FIXMAP_PMAP_BEGIN; + + __clear_bit(idx, inuse); + arch_pmap_unmap(slot); +} + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ diff --git a/xen/include/xen/pmap.h b/xen/include/xen/pmap.h new file mode 100644 index 0000000000..93e61b1087 --- /dev/null +++ b/xen/include/xen/pmap.h @@ -0,0 +1,16 @@ +#ifndef __XEN_PMAP_H__ +#define __XEN_PMAP_H__ + +/* Large enough for mapping 5 levels of page tables with some headroom */ +#define NUM_FIX_PMAP 8 + +#ifndef __ASSEMBLY__ + +#include <xen/mm-frame.h> + +void *pmap_map(mfn_t mfn); +void pmap_unmap(const void *p); + +#endif /* __ASSEMBLY__ */ + +#endif /* __XEN_PMAP_H__ */ -- generated by git-patchbot for /home/xen/git/xen.git#staging
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