Skip to content

Commit

Permalink
KVM: VMX: Separate saving pre-realmode state from setting segments
Browse files Browse the repository at this point in the history
Commit b246dd5 ("KVM: VMX: Fix KVM_SET_SREGS with big real mode
segments") moved fix_rmode_seg() to vmx_set_segment(), so that it is
applied not just on transitions to real mode, but also on KVM_SET_SREGS
(migration).  However fix_rmode_seg() not only munges the vmcs segments,
it also sets up the save area for us to restore when returning to
protected mode or to return in vmx_get_segment().

Move saving the segment into a new function, save_rmode_seg(), and
call it just during the transition.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
  • Loading branch information
Avi Kivity authored and Marcelo Tosatti committed Aug 27, 2012
1 parent dd856ef commit baa7e81
Showing 1 changed file with 13 additions and 7 deletions.
20 changes: 13 additions & 7 deletions arch/x86/kvm/vmx.c
Original file line number Diff line number Diff line change
Expand Up @@ -2768,14 +2768,20 @@ static gva_t rmode_tss_base(struct kvm *kvm)
return kvm->arch.tss_addr;
}

static void fix_rmode_seg(int seg, struct kvm_save_segment *save)
static void save_rmode_seg(int seg, struct kvm_save_segment *save)
{
struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];

save->selector = vmcs_read16(sf->selector);
save->base = vmcs_readl(sf->base);
save->limit = vmcs_read32(sf->limit);
save->ar = vmcs_read32(sf->ar_bytes);
}

static void fix_rmode_seg(int seg, struct kvm_save_segment *save)
{
struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];

vmcs_write16(sf->selector, save->base >> 4);
vmcs_write32(sf->base, save->base & 0xffff0);
vmcs_write32(sf->limit, 0xffff);
Expand All @@ -2798,6 +2804,12 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
vmx->emulation_required = 1;
vmx->rmode.vm86_active = 1;

save_rmode_seg(VCPU_SREG_TR, &vmx->rmode.tr);
save_rmode_seg(VCPU_SREG_ES, &vmx->rmode.es);
save_rmode_seg(VCPU_SREG_DS, &vmx->rmode.ds);
save_rmode_seg(VCPU_SREG_FS, &vmx->rmode.fs);
save_rmode_seg(VCPU_SREG_GS, &vmx->rmode.gs);

/*
* Very old userspace does not call KVM_SET_TSS_ADDR before entering
* vcpu. Call it here with phys address pointing 16M below 4G.
Expand All @@ -2812,14 +2824,8 @@ static void enter_rmode(struct kvm_vcpu *vcpu)

vmx_segment_cache_clear(vmx);

vmx->rmode.tr.selector = vmcs_read16(GUEST_TR_SELECTOR);
vmx->rmode.tr.base = vmcs_readl(GUEST_TR_BASE);
vmcs_writel(GUEST_TR_BASE, rmode_tss_base(vcpu->kvm));

vmx->rmode.tr.limit = vmcs_read32(GUEST_TR_LIMIT);
vmcs_write32(GUEST_TR_LIMIT, RMODE_TSS_SIZE - 1);

vmx->rmode.tr.ar = vmcs_read32(GUEST_TR_AR_BYTES);
vmcs_write32(GUEST_TR_AR_BYTES, 0x008b);

flags = vmcs_readl(GUEST_RFLAGS);
Expand Down

0 comments on commit baa7e81

Please sign in to comment.