All three code paths mean to only emulate memory writes. Refuse
emulation of any other instructions there.
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
This would effectively allow us to revert 0e47f92b07 ("x86: force
EFLAGS.IF on when exiting to PV guests").
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5340,11 +5340,19 @@ static int ptwr_emulated_cmpxchg(
container_of(ctxt, struct ptwr_emulate_ctxt, ctxt));
}
+static int pv_emul_is_mem_write(const struct x86_emulate_state *state,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return x86_insn_is_mem_write(state, ctxt) ? X86EMUL_OKAY
+ : X86EMUL_UNHANDLEABLE;
+}
+
static const struct x86_emulate_ops ptwr_emulate_ops = {
.read = ptwr_emulated_read,
.insn_fetch = ptwr_emulated_read,
.write = ptwr_emulated_write,
.cmpxchg = ptwr_emulated_cmpxchg,
+ .validate = pv_emul_is_mem_write,
.cpuid = pv_emul_cpuid,
};
@@ -5463,6 +5471,7 @@ static const struct x86_emulate_ops mmio
.read = x86emul_unhandleable_rw,
.insn_fetch = ptwr_emulated_read,
.write = mmio_ro_emulated_write,
+ .validate = pv_emul_is_mem_write,
.cpuid = pv_emul_cpuid,
};
@@ -5501,6 +5510,7 @@ static const struct x86_emulate_ops mmcf
.read = x86emul_unhandleable_rw,
.insn_fetch = ptwr_emulated_read,
.write = mmcfg_intercept_write,
+ .validate = pv_emul_is_mem_write,
.cpuid = pv_emul_cpuid,
};
x86/PV: restrict permitted instructions during memory write emulation
All three code paths mean to only emulate memory writes. Refuse
emulation of any other instructions there.
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
This would effectively allow us to revert 0e47f92b07 ("x86: force
EFLAGS.IF on when exiting to PV guests").
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5340,11 +5340,19 @@ static int ptwr_emulated_cmpxchg(
container_of(ctxt, struct ptwr_emulate_ctxt, ctxt));
}
+static int pv_emul_is_mem_write(const struct x86_emulate_state *state,
+ struct x86_emulate_ctxt *ctxt)
+{
+ return x86_insn_is_mem_write(state, ctxt) ? X86EMUL_OKAY
+ : X86EMUL_UNHANDLEABLE;
+}
+
static const struct x86_emulate_ops ptwr_emulate_ops = {
.read = ptwr_emulated_read,
.insn_fetch = ptwr_emulated_read,
.write = ptwr_emulated_write,
.cmpxchg = ptwr_emulated_cmpxchg,
+ .validate = pv_emul_is_mem_write,
.cpuid = pv_emul_cpuid,
};
@@ -5463,6 +5471,7 @@ static const struct x86_emulate_ops mmio
.read = x86emul_unhandleable_rw,
.insn_fetch = ptwr_emulated_read,
.write = mmio_ro_emulated_write,
+ .validate = pv_emul_is_mem_write,
.cpuid = pv_emul_cpuid,
};
@@ -5501,6 +5510,7 @@ static const struct x86_emulate_ops mmcf
.read = x86emul_unhandleable_rw,
.insn_fetch = ptwr_emulated_read,
.write = mmcfg_intercept_write,
+ .validate = pv_emul_is_mem_write,
.cpuid = pv_emul_cpuid,
};
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