Re: [PATCH 15/24] KVM: x86 emulator: Provide more callbacks for x86 emulator.

[Gleb Natapov <gleb@redhat.com>]

On Tue, Mar 09, 2010 at 04:43:59PM +0200, Avi Kivity wrote:
> On 03/09/2010 04:09 PM, Gleb Natapov wrote:
> >Provide get_cached_descriptor(), set_cached_descriptor(),
> >get_segment_selector(), set_segment_selector(), get_gdt(),
> >write_std() callbacks.
> >
> >Signed-off-by: Gleb Natapov<gleb@redhat.com>
> >---
> >  arch/x86/include/asm/kvm_emulate.h |   16 +++++
> >  arch/x86/kvm/x86.c                 |  130 +++++++++++++++++++++++++++++++----
> >  2 files changed, 131 insertions(+), 15 deletions(-)
> >
> >diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
> >index 032d02f..e881618 100644
> >--- a/arch/x86/include/asm/kvm_emulate.h
> >+++ b/arch/x86/include/asm/kvm_emulate.h
> >@@ -63,6 +63,15 @@ struct x86_emulate_ops {
> >  			unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
> >
> >  	/*
> >+	 * write_std: Write bytes of standard (non-emulated/special) memory.
> >+	 *            Used for descriptor writing.
> >+	 *  @addr:  [IN ] Linear address to which to write.
> >+	 *  @val:   [OUT] Value write to memory, zero-extended to 'u_long'.
> >+	 *  @bytes: [IN ] Number of bytes to write to memory.
> >+	 */
> >+	int (*write_std)(unsigned long addr, void *val,
> >+			 unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
> 
> Descriptor writes need an atomic kvm_set_guest_bit(), no?
> 
It is? atomic against what? Current code just write whole descriptor
using write_std().

--
			Gleb.