ed7d3489df
(generated with debian/scripts/import-upstream-tag) Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
159 lines
4.8 KiB
Diff
159 lines
4.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Maxim Levitsky <mlevitsk@redhat.com>
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Date: Wed, 3 Aug 2022 18:50:01 +0300
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Subject: [PATCH] KVM: x86: emulator: introduce emulator_recalc_and_set_mode
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Some instructions update the cpu execution mode, which needs
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to update the emulation mode.
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Extract this code, and make assign_eip_far use it.
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assign_eip_far now reads CS, instead of getting it via a parameter,
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which is ok, because callers always assign CS to the
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same value before calling it.
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No functional change is intended.
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Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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arch/x86/kvm/emulate.c | 85 ++++++++++++++++++++++++++++--------------
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1 file changed, 57 insertions(+), 28 deletions(-)
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diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
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index d888223ef820..529b9e052564 100644
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--- a/arch/x86/kvm/emulate.c
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+++ b/arch/x86/kvm/emulate.c
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@@ -794,8 +794,7 @@ static int linearize(struct x86_emulate_ctxt *ctxt,
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ctxt->mode, linear);
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}
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-static inline int assign_eip(struct x86_emulate_ctxt *ctxt, ulong dst,
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- enum x86emul_mode mode)
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+static inline int assign_eip(struct x86_emulate_ctxt *ctxt, ulong dst)
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{
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ulong linear;
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int rc;
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@@ -805,41 +804,71 @@ static inline int assign_eip(struct x86_emulate_ctxt *ctxt, ulong dst,
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if (ctxt->op_bytes != sizeof(unsigned long))
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addr.ea = dst & ((1UL << (ctxt->op_bytes << 3)) - 1);
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- rc = __linearize(ctxt, addr, &max_size, 1, false, true, mode, &linear);
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+ rc = __linearize(ctxt, addr, &max_size, 1, false, true, ctxt->mode, &linear);
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if (rc == X86EMUL_CONTINUE)
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ctxt->_eip = addr.ea;
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return rc;
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}
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+static inline int emulator_recalc_and_set_mode(struct x86_emulate_ctxt *ctxt)
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+{
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+ u64 efer;
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+ struct desc_struct cs;
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+ u16 selector;
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+ u32 base3;
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+
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+ ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
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+
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+ if (!ctxt->ops->get_cr(ctxt, 0) & X86_CR0_PE) {
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+ /* Real mode. cpu must not have long mode active */
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+ if (efer & EFER_LMA)
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+ return X86EMUL_UNHANDLEABLE;
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+ ctxt->mode = X86EMUL_MODE_REAL;
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+ return X86EMUL_CONTINUE;
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+ }
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+
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+ if (ctxt->eflags & X86_EFLAGS_VM) {
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+ /* Protected/VM86 mode. cpu must not have long mode active */
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+ if (efer & EFER_LMA)
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+ return X86EMUL_UNHANDLEABLE;
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+ ctxt->mode = X86EMUL_MODE_VM86;
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+ return X86EMUL_CONTINUE;
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+ }
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+
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+ if (!ctxt->ops->get_segment(ctxt, &selector, &cs, &base3, VCPU_SREG_CS))
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+ return X86EMUL_UNHANDLEABLE;
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+
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+ if (efer & EFER_LMA) {
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+ if (cs.l) {
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+ /* Proper long mode */
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+ ctxt->mode = X86EMUL_MODE_PROT64;
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+ } else if (cs.d) {
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+ /* 32 bit compatibility mode*/
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+ ctxt->mode = X86EMUL_MODE_PROT32;
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+ } else {
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+ ctxt->mode = X86EMUL_MODE_PROT16;
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+ }
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+ } else {
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+ /* Legacy 32 bit / 16 bit mode */
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+ ctxt->mode = cs.d ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
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+ }
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+
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+ return X86EMUL_CONTINUE;
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+}
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+
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static inline int assign_eip_near(struct x86_emulate_ctxt *ctxt, ulong dst)
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{
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- return assign_eip(ctxt, dst, ctxt->mode);
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+ return assign_eip(ctxt, dst);
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}
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-static int assign_eip_far(struct x86_emulate_ctxt *ctxt, ulong dst,
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- const struct desc_struct *cs_desc)
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+static int assign_eip_far(struct x86_emulate_ctxt *ctxt, ulong dst)
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{
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- enum x86emul_mode mode = ctxt->mode;
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- int rc;
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+ int rc = emulator_recalc_and_set_mode(ctxt);
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-#ifdef CONFIG_X86_64
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- if (ctxt->mode >= X86EMUL_MODE_PROT16) {
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- if (cs_desc->l) {
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- u64 efer = 0;
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+ if (rc != X86EMUL_CONTINUE)
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+ return rc;
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- ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
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- if (efer & EFER_LMA)
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- mode = X86EMUL_MODE_PROT64;
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- } else
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- mode = X86EMUL_MODE_PROT32; /* temporary value */
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- }
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-#endif
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- if (mode == X86EMUL_MODE_PROT16 || mode == X86EMUL_MODE_PROT32)
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- mode = cs_desc->d ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
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- rc = assign_eip(ctxt, dst, mode);
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- if (rc == X86EMUL_CONTINUE)
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- ctxt->mode = mode;
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- return rc;
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+ return assign_eip(ctxt, dst);
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}
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static inline int jmp_rel(struct x86_emulate_ctxt *ctxt, int rel)
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@@ -2172,7 +2201,7 @@ static int em_jmp_far(struct x86_emulate_ctxt *ctxt)
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if (rc != X86EMUL_CONTINUE)
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return rc;
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- rc = assign_eip_far(ctxt, ctxt->src.val, &new_desc);
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+ rc = assign_eip_far(ctxt, ctxt->src.val);
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/* Error handling is not implemented. */
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if (rc != X86EMUL_CONTINUE)
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return X86EMUL_UNHANDLEABLE;
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@@ -2250,7 +2279,7 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
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&new_desc);
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if (rc != X86EMUL_CONTINUE)
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return rc;
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- rc = assign_eip_far(ctxt, eip, &new_desc);
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+ rc = assign_eip_far(ctxt, eip);
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/* Error handling is not implemented. */
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if (rc != X86EMUL_CONTINUE)
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return X86EMUL_UNHANDLEABLE;
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@@ -3470,7 +3499,7 @@ static int em_call_far(struct x86_emulate_ctxt *ctxt)
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if (rc != X86EMUL_CONTINUE)
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return rc;
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- rc = assign_eip_far(ctxt, ctxt->src.val, &new_desc);
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+ rc = assign_eip_far(ctxt, ctxt->src.val);
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if (rc != X86EMUL_CONTINUE)
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goto fail;
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