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Date: Fri, 7 Aug 2020 10:38:22 +0200
From: Juergen Gross <jgross@...e.com>
To: xen-devel@...ts.xenproject.org, x86@...nel.org,
linux-kernel@...r.kernel.org
Cc: Juergen Gross <jgross@...e.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Stefano Stabellini <sstabellini@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v3 3/7] x86/xen: drop tests for highmem in pv code
With support for 32-bit pv guests gone pure pv-code no longer needs to
test for highmem. Dropping those tests removes the need for flushing
in some places.
Signed-off-by: Juergen Gross <jgross@...e.com>
---
arch/x86/xen/enlighten_pv.c | 11 ++-
arch/x86/xen/mmu_pv.c | 138 ++++++++++++++----------------------
2 files changed, 57 insertions(+), 92 deletions(-)
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 7d90b3da8bb4..9fec952f84f3 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -347,6 +347,7 @@ static void set_aliased_prot(void *v, pgprot_t prot)
unsigned long pfn;
struct page *page;
unsigned char dummy;
+ void *av;
ptep = lookup_address((unsigned long)v, &level);
BUG_ON(ptep == NULL);
@@ -383,14 +384,10 @@ static void set_aliased_prot(void *v, pgprot_t prot)
if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
BUG();
- if (!PageHighMem(page)) {
- void *av = __va(PFN_PHYS(pfn));
+ av = __va(PFN_PHYS(pfn));
- if (av != v)
- if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
- BUG();
- } else
- kmap_flush_unused();
+ if (av != v && HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
+ BUG();
preempt_enable();
}
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 1f9500d0b839..3774fa6d2ef7 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -537,25 +537,26 @@ __visible p4d_t xen_make_p4d(p4dval_t p4d)
PV_CALLEE_SAVE_REGS_THUNK(xen_make_p4d);
#endif /* CONFIG_PGTABLE_LEVELS >= 5 */
-static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
- int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
- bool last, unsigned long limit)
+static void xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
+ void (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ bool last, unsigned long limit)
{
- int i, nr, flush = 0;
+ int i, nr;
nr = last ? pmd_index(limit) + 1 : PTRS_PER_PMD;
for (i = 0; i < nr; i++) {
if (!pmd_none(pmd[i]))
- flush |= (*func)(mm, pmd_page(pmd[i]), PT_PTE);
+ (*func)(mm, pmd_page(pmd[i]), PT_PTE);
}
- return flush;
}
-static int xen_pud_walk(struct mm_struct *mm, pud_t *pud,
- int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
- bool last, unsigned long limit)
+static void xen_pud_walk(struct mm_struct *mm, pud_t *pud,
+ void (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ bool last, unsigned long limit)
{
- int i, nr, flush = 0;
+ int i, nr;
nr = last ? pud_index(limit) + 1 : PTRS_PER_PUD;
for (i = 0; i < nr; i++) {
@@ -566,29 +567,26 @@ static int xen_pud_walk(struct mm_struct *mm, pud_t *pud,
pmd = pmd_offset(&pud[i], 0);
if (PTRS_PER_PMD > 1)
- flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
- flush |= xen_pmd_walk(mm, pmd, func,
- last && i == nr - 1, limit);
+ (*func)(mm, virt_to_page(pmd), PT_PMD);
+ xen_pmd_walk(mm, pmd, func, last && i == nr - 1, limit);
}
- return flush;
}
-static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
- int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
- bool last, unsigned long limit)
+static void xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
+ void (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ bool last, unsigned long limit)
{
- int flush = 0;
pud_t *pud;
if (p4d_none(*p4d))
- return flush;
+ return;
pud = pud_offset(p4d, 0);
if (PTRS_PER_PUD > 1)
- flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
- flush |= xen_pud_walk(mm, pud, func, last, limit);
- return flush;
+ (*func)(mm, virt_to_page(pud), PT_PUD);
+ xen_pud_walk(mm, pud, func, last, limit);
}
/*
@@ -603,12 +601,12 @@ static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
* We must skip the Xen hole in the middle of the address space, just after
* the big x86-64 virtual hole.
*/
-static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
- int (*func)(struct mm_struct *mm, struct page *,
- enum pt_level),
- unsigned long limit)
+static void __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
+ void (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
{
- int i, nr, flush = 0;
+ int i, nr;
unsigned hole_low = 0, hole_high = 0;
/* The limit is the last byte to be touched */
@@ -633,22 +631,20 @@ static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
continue;
p4d = p4d_offset(&pgd[i], 0);
- flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
+ xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
}
/* Do the top level last, so that the callbacks can use it as
a cue to do final things like tlb flushes. */
- flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
-
- return flush;
+ (*func)(mm, virt_to_page(pgd), PT_PGD);
}
-static int xen_pgd_walk(struct mm_struct *mm,
- int (*func)(struct mm_struct *mm, struct page *,
- enum pt_level),
- unsigned long limit)
+static void xen_pgd_walk(struct mm_struct *mm,
+ void (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
{
- return __xen_pgd_walk(mm, mm->pgd, func, limit);
+ __xen_pgd_walk(mm, mm->pgd, func, limit);
}
/* If we're using split pte locks, then take the page's lock and
@@ -681,26 +677,17 @@ static void xen_do_pin(unsigned level, unsigned long pfn)
xen_extend_mmuext_op(&op);
}
-static int xen_pin_page(struct mm_struct *mm, struct page *page,
- enum pt_level level)
+static void xen_pin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
{
unsigned pgfl = TestSetPagePinned(page);
- int flush;
-
- if (pgfl)
- flush = 0; /* already pinned */
- else if (PageHighMem(page))
- /* kmaps need flushing if we found an unpinned
- highpage */
- flush = 1;
- else {
+
+ if (!pgfl) {
void *pt = lowmem_page_address(page);
unsigned long pfn = page_to_pfn(page);
struct multicall_space mcs = __xen_mc_entry(0);
spinlock_t *ptl;
- flush = 0;
-
/*
* We need to hold the pagetable lock between the time
* we make the pagetable RO and when we actually pin
@@ -737,8 +724,6 @@ static int xen_pin_page(struct mm_struct *mm, struct page *page,
xen_mc_callback(xen_pte_unlock, ptl);
}
}
-
- return flush;
}
/* This is called just after a mm has been created, but it has not
@@ -752,14 +737,7 @@ static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
xen_mc_batch();
- if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
- /* re-enable interrupts for flushing */
- xen_mc_issue(0);
-
- kmap_flush_unused();
-
- xen_mc_batch();
- }
+ __xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT);
xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
@@ -803,11 +781,10 @@ void xen_mm_pin_all(void)
spin_unlock(&pgd_lock);
}
-static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
- enum pt_level level)
+static void __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
{
SetPagePinned(page);
- return 0;
}
/*
@@ -823,12 +800,12 @@ static void __init xen_after_bootmem(void)
xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
}
-static int xen_unpin_page(struct mm_struct *mm, struct page *page,
- enum pt_level level)
+static void xen_unpin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
{
unsigned pgfl = TestClearPagePinned(page);
- if (pgfl && !PageHighMem(page)) {
+ if (pgfl) {
void *pt = lowmem_page_address(page);
unsigned long pfn = page_to_pfn(page);
spinlock_t *ptl = NULL;
@@ -859,8 +836,6 @@ static int xen_unpin_page(struct mm_struct *mm, struct page *page,
xen_mc_callback(xen_pte_unlock, ptl);
}
}
-
- return 0; /* never need to flush on unpin */
}
/* Release a pagetables pages back as normal RW */
@@ -1554,20 +1529,14 @@ static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
if (static_branch_likely(&xen_struct_pages_ready))
SetPagePinned(page);
- if (!PageHighMem(page)) {
- xen_mc_batch();
+ xen_mc_batch();
- __set_pfn_prot(pfn, PAGE_KERNEL_RO);
+ __set_pfn_prot(pfn, PAGE_KERNEL_RO);
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
- __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+ if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
+ __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
- xen_mc_issue(PARAVIRT_LAZY_MMU);
- } else {
- /* make sure there are no stray mappings of
- this page */
- kmap_flush_unused();
- }
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
}
}
@@ -1590,16 +1559,15 @@ static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
trace_xen_mmu_release_ptpage(pfn, level, pinned);
if (pinned) {
- if (!PageHighMem(page)) {
- xen_mc_batch();
+ xen_mc_batch();
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
- __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+ if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
+ __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
- __set_pfn_prot(pfn, PAGE_KERNEL);
+ __set_pfn_prot(pfn, PAGE_KERNEL);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
- xen_mc_issue(PARAVIRT_LAZY_MMU);
- }
ClearPagePinned(page);
}
}
--
2.26.2
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