Commit 35fd68a3 authored Apr 08, 2015 by Wanpeng Li Committed by Paolo Bonzini Apr 08, 2015

kvm: x86: fix x86 eflags fixed bit



Guest can't be booted w/ ept=0, there is a message dumped as below:

If you're running a guest on an Intel machine without unrestricted mode
support, the failure can be most likely due to the guest entering an invalid
state for Intel VT. For example, the guest maybe running in big real mode
which is not supported on less recent Intel processors.

EAX=00000011 EBX=f000d2f6 ECX=00006cac EDX=000f8956
ESI=bffbdf62 EDI=00000000 EBP=00006c68 ESP=00006c68
EIP=0000d187 EFL=00000004 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =e000 000e0000 ffffffff 00809300 DPL=0 DS16 [-WA]
CS =f000 000f0000 ffffffff 00809b00 DPL=0 CS16 [-RA]
SS =0000 00000000 ffffffff 00809300 DPL=0 DS16 [-WA]
DS =0000 00000000 ffffffff 00809300 DPL=0 DS16 [-WA]
FS =0000 00000000 ffffffff 00809300 DPL=0 DS16 [-WA]
GS =0000 00000000 ffffffff 00809300 DPL=0 DS16 [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
GDT=     000f6a80 00000037
IDT=     000f6abe 00000000
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=01 1e b8 6a 2e 0f 01 16 74 6a 0f 20 c0 66 83 c8 01 0f 22 c0 <66> ea 8f d1 0f 00 08 00 b8 10 00 00 00 8e d8 8e c0 8e d0 8e e0 8e e8 89 c8 ff e2 89 c1 b8X

X86 eflags bit 1 is fixed set, which means that 1 << 1 is set instead of 1,
this patch fix it.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Message-Id: <1428473294-6633-1-git-send-email-wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 7f22b45d

arch/x86/kvm/emulate.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -2033,7 +2033,7 @@ static int emulate_iret_real(struct x86_emulate_ctxt *ctxt)
		X86_EFLAGS_IF \| X86_EFLAGS_DF \| X86_EFLAGS_OF \|
		X86_EFLAGS_IOPL \| X86_EFLAGS_NT \| X86_EFLAGS_RF \|
		X86_EFLAGS_AC \| X86_EFLAGS_ID \|
		X86_EFLAGS_FIXED_BIT;
		X86_EFLAGS_FIXED;
		unsigned long vm86_mask = X86_EFLAGS_VM \| X86_EFLAGS_VIF \|
		X86_EFLAGS_VIP;

		@@ -2072,7 +2072,7 @@ static int emulate_iret_real(struct x86_emulate_ctxt *ctxt)
		}

		ctxt->eflags &= ~EFLG_RESERVED_ZEROS_MASK; /* Clear reserved zeros */
		ctxt->eflags \|= X86_EFLAGS_FIXED_BIT;
		ctxt->eflags \|= X86_EFLAGS_FIXED;
		ctxt->ops->set_nmi_mask(ctxt, false);

		return rc;
		@@ -2390,7 +2390,7 @@ static int em_syscall(struct x86_emulate_ctxt *ctxt)

		ops->get_msr(ctxt, MSR_SYSCALL_MASK, &msr_data);
		ctxt->eflags &= ~msr_data;
		ctxt->eflags \|= X86_EFLAGS_FIXED_BIT;
		ctxt->eflags \|= X86_EFLAGS_FIXED;
		#endif
		} else {
		/* legacy mode */

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