Re: [PATCH] Fix migration of real mode guests from host with unrestricted guest to a host without it.
On 05/31/2012 02:13 PM, Orit Wasserman wrote:
> For example migration between Westmere and Nehelem hosts.
> The patch fixes the guest segments similar to enter_rmode function.
>
> Signed-off-by: Orit Wasserman
> ---
> arch/x86/kvm/vmx.c | 38 ++
> 1 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 32eb588..2eca18f 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -3229,6 +3229,44 @@ 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, 0x);
> + if (vmcs_readl(GUEST_CS_BASE) == 0x)
> + vmcs_writel(GUEST_CS_BASE, 0xf);
> + 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, 0x);
> + vmcs_write32(GUEST_SS_AR_BYTES, 0xf3);
> + break;
> + }
> + }
> }
>
This duplicates the code in enter_rmode(). Please change enter_rmode()
to vmx_set_segment(vmx_get_segment()) to avoid duplication.
--
error compiling committee.c: too many arguments to function
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[PATCH] Fix migration of real mode guests from host with unrestricted guest to a host without it.
For example migration between Westmere and Nehelem hosts.
The patch fixes the guest segments similar to enter_rmode function.
Signed-off-by: Orit Wasserman
---
arch/x86/kvm/vmx.c | 38 ++
1 files changed, 38 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 32eb588..2eca18f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3229,6 +3229,44 @@ 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, 0x);
+ if (vmcs_readl(GUEST_CS_BASE) == 0x)
+ vmcs_writel(GUEST_CS_BASE, 0xf);
+ 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, 0x);
+ vmcs_write32(GUEST_SS_AR_BYTES, 0xf3);
+ break;
+ }
+ }
}
static void vmx_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
--
1.7.7.6
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