Avoid address_space_rw() with a constant is_write argument

The address_space_rw() function allows either reads or writes
depending on the is_write argument passed to it; this is useful
when the direction of the access is determined programmatically
(as for instance when handling the KVM_EXIT_MMIO exit reason).
Under the hood it just calls either address_space_write() or
address_space_read_full().

We also use it a lot with a constant is_write argument, though,
which has two issues:
 * when reading "address_space_rw(..., 1)" this is less
   immediately clear to the reader as being a write than
   "address_space_write(...)"
 * calling address_space_rw() bypasses the optimization
   in address_space_read() that fast-paths reads of a
   fixed length

This commit was produced with the included Coccinelle script
scripts/coccinelle/exec_rw_const.cocci.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20200218112457.22712-1-peter.maydell@linaro.org>
[PMD: Update macvm_set_cr0() reported by Laurent Vivier]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/target/i386/hvf/vmx.h b/target/i386/hvf/vmx.h
index 19af029133..03d2c79b9c 100644
--- a/target/i386/hvf/vmx.h
+++ b/target/i386/hvf/vmx.h
@@ -125,10 +125,9 @@ static inline void macvm_set_cr0(hv_vcpuid_t vcpu, uint64_t cr0)
 
     if ((cr0 & CR0_PG) && (rvmcs(vcpu, VMCS_GUEST_CR4) & CR4_PAE) &&
         !(efer & MSR_EFER_LME)) {
-        address_space_rw(&address_space_memory,
-                         rvmcs(vcpu, VMCS_GUEST_CR3) & ~0x1f,
-                         MEMTXATTRS_UNSPECIFIED,
-                         pdpte, 32, false);
+        address_space_read(&address_space_memory,
+                           rvmcs(vcpu, VMCS_GUEST_CR3) & ~0x1f,
+                           MEMTXATTRS_UNSPECIFIED, pdpte, 32);
         /* Only set PDPTE when appropriate. */
         for (i = 0; i < 4; i++) {
             wvmcs(vcpu, VMCS_GUEST_PDPTE0 + i * 2, pdpte[i]);