From: Andrew Jones <drjones@redhat.com>
To: kvm@vger.kernel.org, pbonzini@redhat.com
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Subject: [PULL kvm-unit-tests 06/17] lib: arm: Add proper data synchronization barriers for TLBIs
Date: Mon, 6 Jan 2020 11:03:36 +0100 [thread overview]
Message-ID: <20200106100347.1559-7-drjones@redhat.com> (raw)
In-Reply-To: <20200106100347.1559-1-drjones@redhat.com>
From: Alexandru Elisei <alexandru.elisei@arm.com>
We need to issue a DSB before doing TLB invalidation to make sure that the
table walker sees the new VA mapping after the TLBI finishes. For
flush_tlb_page, we do a DSB ISHST (synchronization barrier for writes in
the Inner Shareable domain) because translation table walks are now
coherent for arm. For local_flush_tlb_all, we only need to affect the
Non-shareable domain, and we do a DSB NSHST. We need a synchronization
barrier here, and not a memory ordering barrier, because a table walk is
not a memory operation and therefore not affected by the DMB.
For the same reasons, we downgrade the full system DSB after the TLBI to a
DSB ISH (synchronization barrier for reads and writes in the Inner
Shareable domain), and, respectively, DSB NSH (in the Non-shareable
domain).
With these two changes, our TLB maintenance functions now match what Linux
does in __flush_tlb_kernel_page, and, respectively, in local_flush_tlb_all.
A similar change was implemented in Linux commit 62cbbc42e001 ("ARM: tlb:
reduce scope of barrier domains for TLB invalidation").
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
---
lib/arm/asm/mmu.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/lib/arm/asm/mmu.h b/lib/arm/asm/mmu.h
index 361f3cdcc3d5..2bf8965ed35e 100644
--- a/lib/arm/asm/mmu.h
+++ b/lib/arm/asm/mmu.h
@@ -17,9 +17,10 @@
static inline void local_flush_tlb_all(void)
{
+ dsb(nshst);
/* TLBIALL */
asm volatile("mcr p15, 0, %0, c8, c7, 0" :: "r" (0));
- dsb();
+ dsb(nsh);
isb();
}
@@ -31,9 +32,10 @@ static inline void flush_tlb_all(void)
static inline void flush_tlb_page(unsigned long vaddr)
{
+ dsb(ishst);
/* TLBIMVAAIS */
asm volatile("mcr p15, 0, %0, c8, c3, 3" :: "r" (vaddr));
- dsb();
+ dsb(ish);
isb();
}
--
2.21.0
next prev parent reply other threads:[~2020-01-06 10:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-06 10:03 [PULL kvm-unit-tests 00/17] arm/arm64: fixes and updates Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 01/17] arm: Add missing test name prefix for pl031 and spinlock Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 02/17] arm: Enable the VFP Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 03/17] arm/arm64: PL031: Fix check_rtc_irq Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 04/17] devicetree: Fix the dt_for_each_cpu_node Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 05/17] lib: arm/arm64: Remove unnecessary dcache maintenance operations Andrew Jones
2020-01-06 10:03 ` Andrew Jones [this message]
2020-01-06 10:03 ` [PULL kvm-unit-tests 07/17] lib: Add WRITE_ONCE and READ_ONCE implementations in compiler.h Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 08/17] lib: arm/arm64: Use WRITE_ONCE to update the translation tables Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 09/17] lib: arm/arm64: Remove unused CPU_OFF parameter Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 10/17] lib: arm/arm64: Add missing include for alloc_page.h in pgtable.h Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 11/17] lib: arm: Implement flush_tlb_all Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 12/17] lib: arm/arm64: Teach mmu_clear_user about block mappings Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 13/17] arm64: timer: Write to ICENABLER to disable timer IRQ Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 14/17] lib: arm/arm64: Refuse to disable the MMU with non-identity stack pointer Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 15/17] arm: cstart64.S: Downgrade TLBI to non-shareable in asm_mmu_enable Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 16/17] arm/arm64: Invalidate TLB before enabling MMU Andrew Jones
2020-01-06 10:03 ` [PULL kvm-unit-tests 17/17] arm: cstart64.S: Remove icache invalidation from asm_mmu_enable Andrew Jones
2020-01-08 18:04 ` [PULL kvm-unit-tests 00/17] arm/arm64: fixes and updates Paolo Bonzini
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