[v2,7/8] x86/pagewalk: Support PKS

Commit Message

Andrew Cooper Jan. 10, 2023, 5:18 p.m. UTC

PKS is very similar to the existing PKU behaviour, operating on pagewalks for
any supervisor mapping.

Signed-off-by: Andrew Cooper <[e-mail]>
Reviewed-by: Jan Beulich <[e-mail]>
---
CC: Jan Beulich <[e-mail]>
CC: Roger Pau Monné <[e-mail]>
CC: Wei Liu <[e-mail]>
---
 xen/arch/x86/include/asm/guest_pt.h | 5 +++++
 xen/arch/x86/include/asm/hvm/hvm.h  | 3 +++
 xen/arch/x86/mm/guest_walk.c        | 9 +++++----
 3 files changed, 13 insertions(+), 4 deletions(-)

Patch

diff --git a/xen/arch/x86/include/asm/guest_pt.h b/xen/arch/x86/include/asm/guest_pt.h
index 6647ccfb8520..6802db2a415a 100644
--- a/xen/arch/x86/include/asm/guest_pt.h
+++ b/xen/arch/x86/include/asm/guest_pt.h
@@ -282,6 +282,11 @@  static always_inline bool guest_pku_enabled(const struct vcpu *v)
     return !is_pv_vcpu(v) && hvm_pku_enabled(v);
 }
 
+static always_inline bool guest_pks_enabled(const struct vcpu *v)
+{
+    return !is_pv_vcpu(v) && hvm_pks_enabled(v);
+}
+
 /* Helpers for identifying whether guest entries have reserved bits set. */
 
 /* Bits reserved because of maxphysaddr, and (lack of) EFER.NX */
diff --git a/xen/arch/x86/include/asm/hvm/hvm.h b/xen/arch/x86/include/asm/hvm/hvm.h
index 93254651f2f5..65768c797ea7 100644
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -407,6 +407,8 @@  int hvm_get_param(struct domain *d, uint32_t index, uint64_t *value);
     ((v)->arch.hvm.guest_efer & EFER_NXE)
 #define hvm_pku_enabled(v) \
     (hvm_paging_enabled(v) && ((v)->arch.hvm.guest_cr[4] & X86_CR4_PKE))
+#define hvm_pks_enabled(v) \
+    (hvm_paging_enabled(v) && ((v)->arch.hvm.guest_cr[4] & X86_CR4_PKS))
 
 /* Can we use superpages in the HAP p2m table? */
 #define hap_has_1gb (!!(hvm_funcs.hap_capabilities & HVM_HAP_SUPERPAGE_1GB))
@@ -911,6 +913,7 @@  static inline void hvm_set_reg(struct vcpu *v, unsigned int reg, uint64_t val)
 #define hvm_smap_enabled(v) ((void)(v), false)
 #define hvm_nx_enabled(v) ((void)(v), false)
 #define hvm_pku_enabled(v) ((void)(v), false)
+#define hvm_pks_enabled(v) ((void)(v), false)
 
 #define arch_vcpu_block(v) ((void)(v))
 
diff --git a/xen/arch/x86/mm/guest_walk.c b/xen/arch/x86/mm/guest_walk.c
index 161a61b8f5ca..76b4e0425887 100644
--- a/xen/arch/x86/mm/guest_walk.c
+++ b/xen/arch/x86/mm/guest_walk.c
@@ -406,16 +406,17 @@  guest_walk_tables(const struct vcpu *v, struct p2m_domain *p2m,
 #if GUEST_PAGING_LEVELS >= 4 /* 64-bit only... */
     /*
      * If all access checks are thus far ok, check Protection Key for 64bit
-     * data accesses to user mappings.
+     * data accesses.
      *
      * N.B. In the case that the walk ended with a superpage, the fabricated
      * gw->l1e contains the appropriate leaf pkey.
      */
-    if ( (ar & _PAGE_USER) && !(walk & PFEC_insn_fetch) &&
-         guest_pku_enabled(v) )
+    if ( !(walk & PFEC_insn_fetch) &&
+         ((ar & _PAGE_USER) ? guest_pku_enabled(v)
+                            : guest_pks_enabled(v)) )
     {
         unsigned int pkey = guest_l1e_get_pkey(gw->l1e);
-        unsigned int pkr = rdpkru();
+        unsigned int pkr = (ar & _PAGE_USER) ? rdpkru() : rdpkrs();
         unsigned int pk_ar = (pkr >> (pkey * PKEY_WIDTH)) & (PKEY_AD | PKEY_WD);
 
         if ( (pk_ar & PKEY_AD) ||