File 5bd076e9-x86-init-vcpu-debug-regs-correctly.patch of Package xen.9798

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File 5bd076e9-x86-init-vcpu-debug-regs-correctly.patch of Package xen.9798

# Commit dfba4d2e91f63a8f40493c4fc2db03fd8287f6cb
# Date 2018-10-24 14:43:05 +0100
# Author Andrew Cooper <andrew.cooper3@citrix.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
x86/domain: Initialise vcpu debug registers correctly

In particular, initialising %dr6 with the value 0 is buggy, because on
hardware supporting Transactional Memory, it will cause the sticky RTM bit to
be asserted, even though a debug exception from a transaction hasn't actually
been observed.

Introduce arch_vcpu_regs_init() to set various architectural defaults, and
reuse this in the hvm_vcpu_reset_state() path.

Architecturally, %edx's init state contains the processors model information,
and 0xf looks to be a remnant of the old Intel processors.  We clearly have no
software which cares, seeing as it is wrong for the last decade's worth of
Intel hardware and for all other vendors, so lets use the value 0 for
simplicity.

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

# Commit 0a1fa635029d100d4b6b7eddb31d49603217cab7
# Date 2018-10-30 13:26:21 +0000
# Author Andrew Cooper <andrew.cooper3@citrix.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
x86/domain: Fix build with GCC 4.3.x

GCC 4.3.x can't initialise the user_regs structure like this.

Reported-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -327,6 +327,17 @@ void free_vcpu_struct(struct vcpu *v)
     free_xenheap_page(v);
 }
 
+/* Initialise various registers to their architectural INIT/RESET state. */
+void arch_vcpu_regs_init(struct vcpu *v)
+{
+    memset(&v->arch.user_regs, 0, sizeof(v->arch.user_regs));
+    v->arch.user_regs.eflags = X86_EFLAGS_MBS;
+
+    memset(v->arch.debugreg, 0, sizeof(v->arch.debugreg));
+    v->arch.debugreg[6] = X86_DR6_DEFAULT;
+    v->arch.debugreg[7] = X86_DR7_DEFAULT;
+}
+
 int vcpu_initialise(struct vcpu *v)
 {
     struct domain *d = v->domain;
@@ -346,6 +357,8 @@ int vcpu_initialise(struct vcpu *v)
             return rc;
 
         vmce_init_vcpu(v);
+
+        arch_vcpu_regs_init(v);
     }
     else if ( (rc = xstate_alloc_save_area(v)) != 0 )
         return rc;
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3884,11 +3884,9 @@ void hvm_vcpu_reset_state(struct vcpu *v
     }
 
     v->arch.vgc_flags = VGCF_online;
-    memset(&v->arch.user_regs, 0, sizeof(v->arch.user_regs));
-    v->arch.user_regs.rflags = X86_EFLAGS_MBS;
-    v->arch.user_regs.rdx = 0x00000f00;
+
+    arch_vcpu_regs_init(v);
     v->arch.user_regs.rip = ip;
-    memset(&v->arch.debugreg, 0, sizeof(v->arch.debugreg));
 
     v->arch.hvm_vcpu.guest_cr[0] = X86_CR0_ET;
     hvm_update_guest_cr(v, 0);
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -646,6 +646,8 @@ static inline void free_vcpu_guest_conte
     vfree(vgc);
 }
 
+void arch_vcpu_regs_init(struct vcpu *v);
+
 struct vcpu_hvm_context;
 int arch_set_info_hvm_guest(struct vcpu *v, const struct vcpu_hvm_context *ctx);

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File 5bd076e9-x86-init-vcpu-debug-regs-correctly.patch of Package xen.9798

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