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Subject[PATCH 17/52] KVM: VMX: Force seg.base == (seg.sel << 4) in real mode
Date
From: Jan Kiszka <jan.kiszka@siemens.com>

Ensure that segment.base == segment.selector << 4 when entering the real
mode on Intel so that the CPU will not bark at us. This fixes some old
protected mode demo from http://www.x86.org/articles/pmbasics/tspec_a1_doc.htm.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
drivers/kvm/vmx.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index c23f399..fbe792d 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1165,7 +1165,8 @@ static void fix_rmode_seg(int seg, struct kvm_save_segment *save)
save->base = vmcs_readl(sf->base);
save->limit = vmcs_read32(sf->limit);
save->ar = vmcs_read32(sf->ar_bytes);
- vmcs_write16(sf->selector, vmcs_readl(sf->base) >> 4);
+ vmcs_write16(sf->selector, save->base >> 4);
+ vmcs_write32(sf->base, save->base & 0xfffff);
vmcs_write32(sf->limit, 0xffff);
vmcs_write32(sf->ar_bytes, 0xf3);
}
--
1.5.3.7


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