From 2f3881255e6a50d9821f390972b07c1e9d9de626 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 8 Mar 2018 15:58:15 +0100 Subject: [PATCH 02/17] address_space_write: address_space_to_flatview needs RCU lock RH-Author: Paolo Bonzini Message-id: <20180308155819.20598-3-pbonzini@redhat.com> Patchwork-id: 79191 O-Subject: [RHEL7.5 qemu-kvm-rhev PATCH 2/6] address_space_write: address_space_to_flatview needs RCU lock Bugzilla: 1554930 RH-Acked-by: Cornelia Huck RH-Acked-by: Thomas Huth RH-Acked-by: Laurent Vivier address_space_write is calling address_space_to_flatview but it can be called outside the RCU lock. To fix it, push the rcu_read_lock/unlock pair up from flatview_write to address_space_write. Reviewed-by: Alexey Kardashevskiy Signed-off-by: Paolo Bonzini (cherry pick from commit 4c6ebbb364aa6f42c5d8e83e932e967eb83f0e44) Signed-off-by: Miroslav Rezanina --- exec.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) diff --git a/exec.c b/exec.c index 5a12e55..8b50133 100644 --- a/exec.c +++ b/exec.c @@ -2942,6 +2942,7 @@ static MemTxResult flatview_write_continue(FlatView *fv, hwaddr addr, return result; } +/* Called from RCU critical section. */ static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs, const uint8_t *buf, int len) { @@ -2950,25 +2951,14 @@ static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs, MemoryRegion *mr; MemTxResult result = MEMTX_OK; - if (len > 0) { - rcu_read_lock(); - l = len; - mr = flatview_translate(fv, addr, &addr1, &l, true); - result = flatview_write_continue(fv, addr, attrs, buf, len, - addr1, l, mr); - rcu_read_unlock(); - } + l = len; + mr = flatview_translate(fv, addr, &addr1, &l, true); + result = flatview_write_continue(fv, addr, attrs, buf, len, + addr1, l, mr); return result; } -MemTxResult address_space_write(AddressSpace *as, hwaddr addr, - MemTxAttrs attrs, - const uint8_t *buf, int len) -{ - return flatview_write(address_space_to_flatview(as), addr, attrs, buf, len); -} - /* Called within RCU critical section. */ MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr, MemTxAttrs attrs, uint8_t *buf, @@ -3077,6 +3067,23 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, addr, attrs, buf, len, is_write); } +MemTxResult address_space_write(AddressSpace *as, hwaddr addr, + MemTxAttrs attrs, + const uint8_t *buf, int len) +{ + MemTxResult result = MEMTX_OK; + FlatView *fv; + + if (len > 0) { + rcu_read_lock(); + fv = address_space_to_flatview(as); + result = flatview_write(fv, addr, attrs, buf, len); + rcu_read_unlock(); + } + + return result; +} + void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf, int len, int is_write) { -- 1.8.3.1