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Go Back   Linux Archive > Ubuntu > Ubuntu Kernel Team

 
 
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Old 09-27-2012, 02:27 PM
 
Default Revert "KVM: VMX: Fix KVM_SET_SREGS with big real mode segments"

From: Joseph Salisbury <joseph.salisbury@canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1045027

This reverts commit b398aa3174cdfd4d85964fa84004e53ce6a13cab.
---
arch/x86/kvm/vmx.c | 70 +++++++++-------------------------------------------
1 file changed, 12 insertions(+), 58 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b2a349d..576a235 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -618,10 +618,6 @@ static void kvm_cpu_vmxon(u64 addr);
static void kvm_cpu_vmxoff(void);
static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr);
-static void vmx_set_segment(struct kvm_vcpu *vcpu,
- struct kvm_segment *var, int seg);
-static void vmx_get_segment(struct kvm_vcpu *vcpu,
- struct kvm_segment *var, int seg);

static DEFINE_PER_CPU(struct vmcs *, vmxarea);
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -2791,7 +2787,6 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
{
unsigned long flags;
struct vcpu_vmx *vmx = to_vmx(vcpu);
- struct kvm_segment var;

if (enable_unrestricted_guest)
return;
@@ -2835,23 +2830,20 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
if (emulate_invalid_guest_state)
goto continue_rmode;

- vmx_get_segment(vcpu, &var, VCPU_SREG_SS);
- vmx_set_segment(vcpu, &var, VCPU_SREG_SS);
-
- vmx_get_segment(vcpu, &var, VCPU_SREG_CS);
- vmx_set_segment(vcpu, &var, VCPU_SREG_CS);
-
- vmx_get_segment(vcpu, &var, VCPU_SREG_ES);
- vmx_set_segment(vcpu, &var, VCPU_SREG_ES);
+ vmcs_write16(GUEST_SS_SELECTOR, vmcs_readl(GUEST_SS_BASE) >> 4);
+ vmcs_write32(GUEST_SS_LIMIT, 0xffff);
+ vmcs_write32(GUEST_SS_AR_BYTES, 0xf3);

- vmx_get_segment(vcpu, &var, VCPU_SREG_DS);
- vmx_set_segment(vcpu, &var, VCPU_SREG_DS);
+ vmcs_write32(GUEST_CS_AR_BYTES, 0xf3);
+ vmcs_write32(GUEST_CS_LIMIT, 0xffff);
+ if (vmcs_readl(GUEST_CS_BASE) == 0xffff0000)
+ vmcs_writel(GUEST_CS_BASE, 0xf0000);
+ vmcs_write16(GUEST_CS_SELECTOR, vmcs_readl(GUEST_CS_BASE) >> 4);

- vmx_get_segment(vcpu, &var, VCPU_SREG_GS);
- vmx_set_segment(vcpu, &var, VCPU_SREG_GS);
-
- vmx_get_segment(vcpu, &var, VCPU_SREG_FS);
- vmx_set_segment(vcpu, &var, VCPU_SREG_FS);
+ fix_rmode_seg(VCPU_SREG_ES, &vmx->rmode.es);
+ fix_rmode_seg(VCPU_SREG_DS, &vmx->rmode.ds);
+ fix_rmode_seg(VCPU_SREG_GS, &vmx->rmode.gs);
+ fix_rmode_seg(VCPU_SREG_FS, &vmx->rmode.fs);

continue_rmode:
kvm_mmu_reset_context(vcpu);
@@ -3256,44 +3248,6 @@ static void vmx_set_segment(struct kvm_vcpu *vcpu,

vmcs_write32(sf->ar_bytes, ar);
__clear_bit(VCPU_EXREG_CPL, (ulong *)&vcpu->arch.regs_avail);
-
- /*
- * Fix segments for real mode guest in hosts that don't have
- * "unrestricted_mode" or it was disabled.
- * This is done to allow migration of the guests from hosts with
- * unrestricted guest like Westmere to older host that don't have
- * unrestricted guest like Nehelem.
- */
- if (!enable_unrestricted_guest && vmx->rmode.vm86_active) {
- switch (seg) {
- case VCPU_SREG_CS:
- vmcs_write32(GUEST_CS_AR_BYTES, 0xf3);
- vmcs_write32(GUEST_CS_LIMIT, 0xffff);
- if (vmcs_readl(GUEST_CS_BASE) == 0xffff0000)
- vmcs_writel(GUEST_CS_BASE, 0xf0000);
- vmcs_write16(GUEST_CS_SELECTOR,
- vmcs_readl(GUEST_CS_BASE) >> 4);
- break;
- case VCPU_SREG_ES:
- fix_rmode_seg(VCPU_SREG_ES, &vmx->rmode.es);
- break;
- case VCPU_SREG_DS:
- fix_rmode_seg(VCPU_SREG_DS, &vmx->rmode.ds);
- break;
- case VCPU_SREG_GS:
- fix_rmode_seg(VCPU_SREG_GS, &vmx->rmode.gs);
- break;
- case VCPU_SREG_FS:
- fix_rmode_seg(VCPU_SREG_FS, &vmx->rmode.fs);
- break;
- case VCPU_SREG_SS:
- vmcs_write16(GUEST_SS_SELECTOR,
- vmcs_readl(GUEST_SS_BASE) >> 4);
- vmcs_write32(GUEST_SS_LIMIT, 0xffff);
- vmcs_write32(GUEST_SS_AR_BYTES, 0xf3);
- break;
- }
- }
}

static void vmx_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
--
1.7.9.5


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