[PATCH] x86/mm: drop guest_get_eff_l1e()

[PATCH] x86/mm: drop guest_get_eff_l1e()

[Jan Beulich]

There's no actual user of it: pv_ro_page_fault() has a
guest_kernel_mode() conditional around its only call site.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/pv/mm.c
+++ b/xen/arch/x86/pv/mm.c
@@ -56,27 +56,6 @@ l1_pgentry_t *map_guest_l1e(unsigned lon
 }
 
 /*
- * Read the guest's l1e that maps this address, from the kernel-mode
- * page tables.
- */
-static l1_pgentry_t guest_get_eff_kern_l1e(unsigned long linear)
-{
-    struct vcpu *curr = current;
-    const bool user_mode = !(curr->arch.flags & TF_kernel_mode);
-    l1_pgentry_t l1e;
-
-    if ( user_mode )
-        toggle_guest_pt(curr);
-
-    l1e = guest_get_eff_l1e(linear);
-
-    if ( user_mode )
-        toggle_guest_pt(curr);
-
-    return l1e;
-}
-
-/*
  * Map a guest's LDT page (covering the byte at @offset from start of the LDT)
  * into Xen's virtual range.  Returns true if the mapping changed, false
  * otherwise.
--- a/xen/arch/x86/pv/mm.h
+++ b/xen/arch/x86/pv/mm.h
@@ -5,8 +5,11 @@ l1_pgentry_t *map_guest_l1e(unsigned lon
 
 int new_guest_cr3(mfn_t mfn);
 
-/* Read a PV guest's l1e that maps this linear address. */
-static inline l1_pgentry_t guest_get_eff_l1e(unsigned long linear)
+/*
+ * Read the guest's l1e that maps this address, from the kernel-mode
+ * page tables.
+ */
+static inline l1_pgentry_t guest_get_eff_kern_l1e(unsigned long linear)
 {
     l1_pgentry_t l1e;
 
--- a/xen/arch/x86/pv/ro-page-fault.c
+++ b/xen/arch/x86/pv/ro-page-fault.c
@@ -342,7 +342,7 @@ int pv_ro_page_fault(unsigned long addr,
     bool mmio_ro;
 
     /* Attempt to read the PTE that maps the VA being accessed. */
-    pte = guest_get_eff_l1e(addr);
+    pte = guest_get_eff_kern_l1e(addr);
 
     /* We are only looking for read-only mappings */
     if ( ((l1e_get_flags(pte) & (_PAGE_PRESENT | _PAGE_RW)) != _PAGE_PRESENT) )

Re: [PATCH] x86/mm: drop guest_get_eff_l1e()

[Andrew Cooper]

On 03/11/2020 10:48, Jan Beulich wrote:
> There's no actual user of it: pv_ro_page_fault() has a
> guest_kernel_mode() conditional around its only call site.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>