When access to descriptor in LDT/GDT wraparound outside long-mode, the address of the descriptor should be truncated to 32-bit. Citing Intel SDM 2.1.1.1 "Global and Local Descriptor Tables in IA-32e Mode": "GDTR and LDTR registers are expanded to 64-bits wide in both IA-32e sub-modes (64-bit mode and compatibility mode)."
So in other cases, we need to truncate. Creating new function to return a pointer to descriptor table to avoid too much code duplication. Signed-off-by: Nadav Amit <[email protected]> --- arch/x86/kvm/emulate.c | 45 ++++++++++++++++++++++++++++++++------------- 1 file changed, 32 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 4fcd9fd..cb6b8ef 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1446,10 +1446,8 @@ static void get_descriptor_table_ptr(struct x86_emulate_ctxt *ctxt, ops->get_gdt(ctxt, dt); } -/* allowed just for 8 bytes segments */ -static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt, - u16 selector, struct desc_struct *desc, - ulong *desc_addr_p) +static int get_descriptor_ptr(struct x86_emulate_ctxt *ctxt, + u16 selector, ulong *desc_addr_p) { struct desc_ptr dt; u16 index = selector >> 3; @@ -1460,8 +1458,32 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt, if (dt.size < index * 8 + 7) return emulate_gp(ctxt, selector & 0xfffc); - *desc_addr_p = addr = dt.address + index * 8; - return ctxt->ops->read_std(ctxt, addr, desc, sizeof *desc, + addr = dt.address + index * 8; + + if (addr >> 32 != 0) { + u64 efer = 0; + + ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); + if (!(efer & EFER_LMA)) + addr &= (u32)-1; + } + + *desc_addr_p = addr; + return X86EMUL_CONTINUE; +} + +/* allowed just for 8 bytes segments */ +static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt, + u16 selector, struct desc_struct *desc, + ulong *desc_addr_p) +{ + int rc; + + rc = get_descriptor_ptr(ctxt, selector, desc_addr_p); + if (rc != X86EMUL_CONTINUE) + return rc; + + return ctxt->ops->read_std(ctxt, *desc_addr_p, desc, sizeof(*desc), &ctxt->exception); } @@ -1469,16 +1491,13 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt, static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt, u16 selector, struct desc_struct *desc) { - struct desc_ptr dt; - u16 index = selector >> 3; + int rc; ulong addr; - get_descriptor_table_ptr(ctxt, selector, &dt); - - if (dt.size < index * 8 + 7) - return emulate_gp(ctxt, selector & 0xfffc); + rc = get_descriptor_ptr(ctxt, selector, &addr); + if (rc != X86EMUL_CONTINUE) + return rc; - addr = dt.address + index * 8; return ctxt->ops->write_std(ctxt, addr, desc, sizeof *desc, &ctxt->exception); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
