x86/pv: Store the data segment selectors outside of cpu_user_regs

In order to support FRED, we're going to have to remove the {ds..gs} fields
from struct cpu_user_regs.  This will impact v->arch.user_regs.

These fields are unused for HVM guests, but for PV hold the selector values
when the vCPU is scheduled out.

Introduce new fields for the selectors in struct pv_vcpu, and update:

 * {save,load}_segments(), context switching
 * arch_{set,set}_info_guest(), hypercalls
 * vcpu_show_registers(), diagnostics
 * dom0_construct(), PV dom0

to use the new storage.  This removes the final user of read_sregs() so drop
it too.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index bc0816c71495d5d44b67f6357837cddef86f45fc..e9c331be6f63faa02bc9cf4597291369a70a93e3 100644 (file)
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1211,10 +1211,10 @@ int arch_set_info_guest(
         v->arch.user_regs.rflags            = c.nat->user_regs.rflags;
         v->arch.user_regs.rsp               = c.nat->user_regs.rsp;
         v->arch.user_regs.ss                = c.nat->user_regs.ss;
-        v->arch.user_regs.es                = c.nat->user_regs.es;
-        v->arch.user_regs.ds                = c.nat->user_regs.ds;
-        v->arch.user_regs.fs                = c.nat->user_regs.fs;
-        v->arch.user_regs.gs                = c.nat->user_regs.gs;
+        v->arch.pv.es                       = c.nat->user_regs.es;
+        v->arch.pv.ds                       = c.nat->user_regs.ds;
+        v->arch.pv.fs                       = c.nat->user_regs.fs;
+        v->arch.pv.gs                       = c.nat->user_regs.gs;
 
         if ( is_pv_domain(d) )
             memcpy(v->arch.pv.trap_ctxt, c.nat->trap_ctxt,
@@ -1238,10 +1238,10 @@ int arch_set_info_guest(
         v->arch.user_regs.eflags            = c.cmp->user_regs.eflags;
         v->arch.user_regs.esp               = c.cmp->user_regs.esp;
         v->arch.user_regs.ss                = c.cmp->user_regs.ss;
-        v->arch.user_regs.es                = c.cmp->user_regs.es;
-        v->arch.user_regs.ds                = c.cmp->user_regs.ds;
-        v->arch.user_regs.fs                = c.cmp->user_regs.fs;
-        v->arch.user_regs.gs                = c.cmp->user_regs.gs;
+        v->arch.pv.es                       = c.nat->user_regs.es;
+        v->arch.pv.ds                       = c.nat->user_regs.ds;
+        v->arch.pv.fs                       = c.nat->user_regs.fs;
+        v->arch.pv.gs                       = c.nat->user_regs.gs;
 
         if ( is_pv_domain(d) )
         {
@@ -1729,7 +1729,6 @@ long do_vcpu_op(int cmd, unsigned int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
  */
 static void load_segments(struct vcpu *n)
 {
-    struct cpu_user_regs *uregs = &n->arch.user_regs;
     unsigned long gsb = 0, gss = 0;
     bool compat = is_pv_32bit_vcpu(n);
     bool all_segs_okay = true, fs_gs_done = false;
@@ -1762,7 +1761,7 @@ static void load_segments(struct vcpu *n)
         if ( !(n->arch.flags & TF_kernel_mode) )
             SWAP(gsb, gss);
 
-        if ( using_svm() && (uregs->fs | uregs->gs) <= 3 )
+        if ( using_svm() && (n->arch.pv.fs | n->arch.pv.gs) <= 3 )
             fs_gs_done = svm_load_segs(n->arch.pv.ldt_ents, LDT_VIRT_START(n),
                                        n->arch.pv.fs_base, gsb, gss);
     }
@@ -1771,12 +1770,12 @@ static void load_segments(struct vcpu *n)
     {
         load_LDT(n);
 
-        TRY_LOAD_SEG(fs, uregs->fs);
-        TRY_LOAD_SEG(gs, uregs->gs);
+        TRY_LOAD_SEG(fs, n->arch.pv.fs);
+        TRY_LOAD_SEG(gs, n->arch.pv.gs);
     }
 
-    TRY_LOAD_SEG(ds, uregs->ds);
-    TRY_LOAD_SEG(es, uregs->es);
+    TRY_LOAD_SEG(ds, n->arch.pv.ds);
+    TRY_LOAD_SEG(es, n->arch.pv.es);
 
     if ( !fs_gs_done && !compat )
     {
@@ -1829,13 +1828,13 @@ static void load_segments(struct vcpu *n)
             }
 
             if ( ret |
-                 put_guest(rflags,      esp - 1) |
-                 put_guest(cs_and_mask, esp - 2) |
-                 put_guest(regs->eip,   esp - 3) |
-                 put_guest(uregs->gs,   esp - 4) |
-                 put_guest(uregs->fs,   esp - 5) |
-                 put_guest(uregs->es,   esp - 6) |
-                 put_guest(uregs->ds,   esp - 7) )
+                 put_guest(rflags,        esp - 1) |
+                 put_guest(cs_and_mask,   esp - 2) |
+                 put_guest(regs->eip,     esp - 3) |
+                 put_guest(n->arch.pv.gs, esp - 4) |
+                 put_guest(n->arch.pv.fs, esp - 5) |
+                 put_guest(n->arch.pv.es, esp - 6) |
+                 put_guest(n->arch.pv.ds, esp - 7) )
                 domain_crash(n->domain,
                              "Error creating compat failsafe callback frame\n");
 
@@ -1861,17 +1860,17 @@ static void load_segments(struct vcpu *n)
         cs_and_mask = (unsigned long)regs->cs |
             ((unsigned long)vcpu_info(n, evtchn_upcall_mask) << 32);
 
-        if ( put_guest(regs->ss,    rsp -  1) |
-             put_guest(regs->rsp,   rsp -  2) |
-             put_guest(rflags,      rsp -  3) |
-             put_guest(cs_and_mask, rsp -  4) |
-             put_guest(regs->rip,   rsp -  5) |
-             put_guest(uregs->gs,   rsp -  6) |
-             put_guest(uregs->fs,   rsp -  7) |
-             put_guest(uregs->es,   rsp -  8) |
-             put_guest(uregs->ds,   rsp -  9) |
-             put_guest(regs->r11,   rsp - 10) |
-             put_guest(regs->rcx,   rsp - 11) )
+        if ( put_guest(regs->ss,      rsp -  1) |
+             put_guest(regs->rsp,     rsp -  2) |
+             put_guest(rflags,        rsp -  3) |
+             put_guest(cs_and_mask,   rsp -  4) |
+             put_guest(regs->rip,     rsp -  5) |
+             put_guest(n->arch.pv.gs, rsp -  6) |
+             put_guest(n->arch.pv.fs, rsp -  7) |
+             put_guest(n->arch.pv.es, rsp -  8) |
+             put_guest(n->arch.pv.ds, rsp -  9) |
+             put_guest(regs->r11,     rsp - 10) |
+             put_guest(regs->rcx,     rsp - 11) )
             domain_crash(n->domain,
                          "Error creating failsafe callback frame\n");
 
@@ -1900,9 +1899,10 @@ static void load_segments(struct vcpu *n)
  */
 static void save_segments(struct vcpu *v)
 {
-    struct cpu_user_regs *regs = &v->arch.user_regs;
-
-    read_sregs(regs);
+    asm ( "mov %%ds, %0" : "=m" (v->arch.pv.ds) );
+    asm ( "mov %%es, %0" : "=m" (v->arch.pv.es) );
+    asm ( "mov %%fs, %0" : "=m" (v->arch.pv.fs) );
+    asm ( "mov %%gs, %0" : "=m" (v->arch.pv.gs) );
 
     if ( !is_pv_32bit_vcpu(v) )
     {

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 7ab9e9176b58d317368e609df82edbbb370aac47..833fcbd4bbb617130ab581369dbf73433f5c2e40 100644 (file)
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1414,10 +1414,10 @@ void arch_get_info_guest(struct vcpu *v, vcpu_guest_context_u c)
         c.nat->user_regs.rflags            = v->arch.user_regs.rflags;
         c.nat->user_regs.rsp               = v->arch.user_regs.rsp;
         c.nat->user_regs.ss                = v->arch.user_regs.ss;
-        c.nat->user_regs.es                = v->arch.user_regs.es;
-        c.nat->user_regs.ds                = v->arch.user_regs.ds;
-        c.nat->user_regs.fs                = v->arch.user_regs.fs;
-        c.nat->user_regs.gs                = v->arch.user_regs.gs;
+        c.nat->user_regs.es                = v->arch.pv.es;
+        c.nat->user_regs.ds                = v->arch.pv.ds;
+        c.nat->user_regs.fs                = v->arch.pv.fs;
+        c.nat->user_regs.gs                = v->arch.pv.gs;
 
         if ( is_pv_domain(d) )
             memcpy(c.nat->trap_ctxt, v->arch.pv.trap_ctxt,
@@ -1441,10 +1441,10 @@ void arch_get_info_guest(struct vcpu *v, vcpu_guest_context_u c)
         c.cmp->user_regs.eflags            = v->arch.user_regs.eflags;
         c.cmp->user_regs.esp               = v->arch.user_regs.esp;
         c.cmp->user_regs.ss                = v->arch.user_regs.ss;
-        c.cmp->user_regs.es                = v->arch.user_regs.es;
-        c.cmp->user_regs.ds                = v->arch.user_regs.ds;
-        c.cmp->user_regs.fs                = v->arch.user_regs.fs;
-        c.cmp->user_regs.gs                = v->arch.user_regs.gs;
+        c.cmp->user_regs.es                = v->arch.pv.es;
+        c.cmp->user_regs.ds                = v->arch.pv.ds;
+        c.cmp->user_regs.fs                = v->arch.pv.fs;
+        c.cmp->user_regs.gs                = v->arch.pv.gs;
 
         if ( is_pv_domain(d) )
         {

diff --git a/xen/arch/x86/include/asm/domain.h b/xen/arch/x86/include/asm/domain.h
index 5fc1d1e5d01a0da2733f5e03f7ac122eee0d1349..7fa409cb305583011d490c41d2ce19b35d0a8f96 100644 (file)
--- a/xen/arch/x86/include/asm/domain.h
+++ b/xen/arch/x86/include/asm/domain.h
@@ -546,6 +546,8 @@ struct pv_vcpu
     bool syscall32_disables_events;
     bool sysenter_disables_events;
 
+    uint16_t ds, es, fs, gs;
+
     /*
      * 64bit segment bases.
      *

diff --git a/xen/arch/x86/include/asm/regs.h b/xen/arch/x86/include/asm/regs.h
index 4f2f06b601612dd1c3774feb08808ea1c7185a21..c05b9207c281503bdba552adf7963cb34abd1f35 100644 (file)
--- a/xen/arch/x86/include/asm/regs.h
+++ b/xen/arch/x86/include/asm/regs.h
@@ -41,12 +41,4 @@
     __sel;                                           \
 })
 
-static inline void read_sregs(struct cpu_user_regs *regs)
-{
-    asm ( "mov %%ds, %0" : "=m" (regs->ds) );
-    asm ( "mov %%es, %0" : "=m" (regs->es) );
-    asm ( "mov %%fs, %0" : "=m" (regs->fs) );
-    asm ( "mov %%gs, %0" : "=m" (regs->gs) );
-}
-
 #endif /* __X86_REGS_H__ */

diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 96e28c7b6a77f9e0f37c528bb0de31c242809e1a..bcaacc7586c080cd7a849379aa8b46f8f09ebb87 100644 (file)
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -1020,8 +1020,10 @@ static int __init dom0_construct(struct boot_info *bi, struct domain *d)
      *  [rAX,rBX,rCX,rDX,rDI,rBP,R8-R15 are zero]
      */
     regs = &v->arch.user_regs;
-    regs->ds = regs->es = regs->fs = regs->gs =
-               (compat ? FLAT_COMPAT_KERNEL_DS : FLAT_KERNEL_DS);
+    v->arch.pv.ds = (compat ? FLAT_COMPAT_KERNEL_DS : FLAT_KERNEL_DS);
+    v->arch.pv.es = (compat ? FLAT_COMPAT_KERNEL_DS : FLAT_KERNEL_DS);
+    v->arch.pv.fs = (compat ? FLAT_COMPAT_KERNEL_DS : FLAT_KERNEL_DS);
+    v->arch.pv.gs = (compat ? FLAT_COMPAT_KERNEL_DS : FLAT_KERNEL_DS);
     regs->ss = (compat ? FLAT_COMPAT_KERNEL_SS : FLAT_KERNEL_SS);
     regs->cs = (compat ? FLAT_COMPAT_KERNEL_CS : FLAT_KERNEL_CS);
     regs->rip = parms.virt_entry;

diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index 23622cdb1440c46540c5f868478a63a1a3449b88..cb06f99021d1e1c018f2beabc524408368d84a03 100644 (file)
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -219,10 +219,10 @@ void vcpu_show_registers(struct vcpu *v)
         state.gsb = gsb;
         state.gss = gss;
 
-        state.ds = v->arch.user_regs.ds;
-        state.es = v->arch.user_regs.es;
-        state.fs = v->arch.user_regs.fs;
-        state.gs = v->arch.user_regs.gs;
+        state.ds = v->arch.pv.ds;
+        state.es = v->arch.pv.es;
+        state.fs = v->arch.pv.fs;
+        state.gs = v->arch.pv.gs;
 
         context = CTXT_pv_guest;
     }