[Xen-devel] [PATCH 09/10] x86/hvm: pkeys, add pkeys support for guest_walk_tables

[Huaitong Han <huaitong.han@xxxxxxxxx>]

This patch adds pkeys support for guest_walk_tables.

Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>

diff --git a/xen/arch/x86/mm/guest_walk.c b/xen/arch/x86/mm/guest_walk.c
index 773454d..7a7ae96 100644
--- a/xen/arch/x86/mm/guest_walk.c
+++ b/xen/arch/x86/mm/guest_walk.c
@@ -124,6 +124,46 @@ void *map_domain_gfn(struct p2m_domain *p2m, gfn_t gfn, 
mfn_t *mfn,
     return map;
 }
 
+#if GUEST_PAGING_LEVELS >= 4
+uint32_t leaf_pte_pkeys_check(struct vcpu *vcpu, uint32_t pfec,
+                uint32_t pte_access, uint32_t pte_pkeys)
+{
+    unsigned int pkru_ad, pkru_wd;
+    unsigned int ff, wf, uf, rsvdf, pkuf;
+
+    uf = pfec & PFEC_user_mode;
+    wf = pfec & PFEC_write_access;
+    rsvdf = pfec & PFEC_reserved_bit;
+    ff = pfec & PFEC_insn_fetch;
+    pkuf = pfec & PFEC_protection_key;
+
+    if (!pkuf)
+        return 0;
+
+    /*
+     * PKU:  additional mechanism by which the paging controls
+    * access to user-mode addresses based on the value in the
+    * PKRU register. A fault is considered as a PKU violation if all
+    * of the following conditions are ture:
+    * 1.CR4_PKE=1.
+    * 2.EFER_LMA=1.
+    * 3.page is present with no reserved bit violations.
+    * 4.the access is not an instruction fetch.
+    * 5.the access is to a user page.
+    * 6.PKRU.AD=1
+    *       or The access is a data write and PKRU.WD=1
+    *            and either CR0.WP=1 or it is a user access.
+    */
+    pkru_ad = READ_PKRU_AD(pte_pkeys);
+    pkru_wd = READ_PKRU_AD(pte_pkeys);
+    if ( hvm_pku_enabled(vcpu) && hvm_long_mode_enabled(vcpu) &&
+        !rsvdf && !ff && (pkru_ad ||
+        (pkru_wd && wf && (hvm_wp_enabled(vcpu) || uf))))
+        return 1;
+
+    return 0;
+}
+#endif
 
 /* Walk the guest pagetables, after the manner of a hardware walker. */
 /* Because the walk is essentially random, it can cause a deadlock 
@@ -141,6 +181,7 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
 #if GUEST_PAGING_LEVELS >= 4 /* 64-bit only... */
     guest_l3e_t *l3p = NULL;
     guest_l4e_t *l4p;
+    uint32_t pkeys;
 #endif
     uint32_t gflags, mflags, iflags, rc = 0;
     bool_t smep = 0, smap = 0;
@@ -225,6 +266,7 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
         goto out;
     /* Get the l3e and check its flags*/
     gw->l3e = l3p[guest_l3_table_offset(va)];
+    pkeys = guest_l3e_get_pkeys(gw->l3e);
     gflags = guest_l3e_get_flags(gw->l3e) ^ iflags;
     if ( !(gflags & _PAGE_PRESENT) ) {
         rc |= _PAGE_PRESENT;
@@ -234,6 +276,9 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
     
     pse1G = (gflags & _PAGE_PSE) && guest_supports_1G_superpages(v); 
 
+    if (pse1G && leaf_pte_pkeys_check(v, pfec, gflags, pkeys))
+        rc |= _PAGE_PK_BIT;
+
     if ( pse1G )
     {
         /* Generate a fake l1 table entry so callers don't all 
@@ -295,7 +340,6 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
     gw->l2e = l2p[guest_l2_table_offset(va)];
 
 #endif /* All levels... */
-
     gflags = guest_l2e_get_flags(gw->l2e) ^ iflags;
     if ( !(gflags & _PAGE_PRESENT) ) {
         rc |= _PAGE_PRESENT;
@@ -305,6 +349,12 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
 
     pse2M = (gflags & _PAGE_PSE) && guest_supports_superpages(v); 
 
+#if GUEST_PAGING_LEVELS >= 4
+    pkeys = guest_l2e_get_pkeys(gw->l2e);
+    if (pse2M && leaf_pte_pkeys_check(v, pfec, gflags, pkeys))
+        rc |= _PAGE_PK_BIT;
+#endif
+
     if ( pse2M )
     {
         /* Special case: this guest VA is in a PSE superpage, so there's
@@ -365,6 +415,11 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m,
             goto out;
         }
         rc |= ((gflags & mflags) ^ mflags);
+#if GUEST_PAGING_LEVELS >= 4
+        pkeys = guest_l1e_get_pkeys(gw->l1e);
+        if (leaf_pte_pkeys_check(v, pfec, gflags, pkeys))
+            rc |= _PAGE_PK_BIT;
+#endif
     }
 
 #if GUEST_PAGING_LEVELS >= 4 /* 64-bit only... */
diff --git a/xen/include/asm-x86/guest_pt.h b/xen/include/asm-x86/guest_pt.h
index f8a0d76..1c0f050 100644
--- a/xen/include/asm-x86/guest_pt.h
+++ b/xen/include/asm-x86/guest_pt.h
@@ -154,6 +154,17 @@ static inline u32 guest_l4e_get_flags(guest_l4e_t gl4e)
 { return l4e_get_flags(gl4e); }
 #endif
 
+static inline u32 guest_l1e_get_pkeys(guest_l1e_t gl1e)
+{ return l1e_get_pkeys(gl1e); }
+static inline u32 guest_l2e_get_pkeys(guest_l2e_t gl2e)
+{ return l2e_get_pkeys(gl2e); }
+static inline u32 guest_l3e_get_pkeys(guest_l3e_t gl3e)
+{ return l3e_get_pkeys(gl3e); }
+#if GUEST_PAGING_LEVELS >= 4
+static inline u32 guest_l4e_get_pkeys(guest_l4e_t gl4e)
+{ return l4e_get_pkeys(gl4e); }
+#endif
+
 static inline guest_l1e_t guest_l1e_from_gfn(gfn_t gfn, u32 flags)
 { return l1e_from_pfn(gfn_x(gfn), flags); }
 static inline guest_l2e_t guest_l2e_from_gfn(gfn_t gfn, u32 flags)
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 68b216c..e421a9d 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -273,6 +273,8 @@ int hvm_girq_dest_2_vcpu_id(struct domain *d, uint8_t dest, 
uint8_t dest_mode);
     (hvm_paging_enabled(v) && ((v)->arch.hvm_vcpu.guest_cr[4] & X86_CR4_SMAP))
 #define hvm_nx_enabled(v) \
     (!!((v)->arch.hvm_vcpu.guest_efer & EFER_NX))
+#define hvm_pku_enabled(v) \
+    (hvm_paging_enabled(v) && ((v)->arch.hvm_vcpu.guest_cr[4] & X86_CR4_PKE))
 
 /* Can we use superpages in the HAP p2m table? */
 #define hvm_hap_has_1gb(d) \
diff --git a/xen/include/asm-x86/x86_64/page.h 
b/xen/include/asm-x86/x86_64/page.h
index 03418ba..7bb5d2d 100644
--- a/xen/include/asm-x86/x86_64/page.h
+++ b/xen/include/asm-x86/x86_64/page.h
@@ -146,6 +146,8 @@ typedef l4_pgentry_t root_pgentry_t;
 
 #define get_pte_pkeys(x) ((int)(get_pte_flags(x) >> _PAGE_PKEY_BIT0) & 0xF)
 
+#define _PAGE_PK_BIT (1U<<_PAGE_PKEY_BIT0)
+
 /* Bit 23 of a 24-bit flag mask. This corresponds to bit 63 of a pte.*/
 #define _PAGE_NX_BIT (1U<<23)
 
-- 
2.4.3


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