[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] Re: [PATCH 4/5] kvmppc: Translate eaddr for fsl_booke mmu

From: Alexander Graf
Subject: [Qemu-devel] Re: [PATCH 4/5] kvmppc: Translate eaddr for fsl_booke mmu
Date: Fri, 21 Aug 2009 14:38:38 +0200

Am 20.08.2009 um 12:21 schrieb "Liu Yu-B13201" <address@hidden>:

-----Original Message-----
From: Hollis Blanchard [mailto:address@hidden
Sent: Thursday, August 20, 2009 6:51 AM
To: Liu Yu-B13201
Cc: address@hidden; address@hidden;
address@hidden; address@hidden; Alexander Graf
Subject: Re: [PATCH 4/5] kvmppc: Translate eaddr for fsl_booke mmu

On Tue, 2009-08-04 at 17:36 +0800, Liu Yu wrote:
Signed-off-by: Liu Yu <address@hidden>
target-ppc/helper.c |   17 +++++++++++++++--
1 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/target-ppc/helper.c b/target-ppc/helper.c
index 6eca2e5..07e56a4 100644
--- a/target-ppc/helper.c
+++ b/target-ppc/helper.c
@@ -22,6 +22,7 @@
#include <string.h>
#include <inttypes.h>
#include <signal.h>
+#include <linux/kvm.h>

#include "cpu.h"
#include "exec-all.h"
@@ -1325,8 +1326,20 @@ static always_inline int
check_physical (CPUState *env, mmu_ctx_t *ctx,
        cpu_abort(env, "MPC8xx MMU model is not implemented\n");
-        /* XXX: TODO */
-        cpu_abort(env, "BookE FSL MMU model not implemented\n");
+        if (kvm_enabled()) {
+            struct kvm_translation tr;
+            /* For now we only debug guest kernel */
+            tr.linear_address = eaddr;
+            ret = kvm_vcpu_ioctl(env, KVM_TRANSLATE, &tr);
+            if (ret < 0)
+                return ret;
+            ctx->raddr = tr.physical_address;
+        } else {
+            /* XXX: TODO */
+            cpu_abort(env, "BookE FSL MMU model not
+        }
        cpu_abort(env, "Unknown or invalid MMU model\n");

One objection: the comment is a little obscure. I think what you're
really saying is "in Linux guests, kernel addresses should always be
covered by TLB1, which means for those addresses we can expect this
ioctl to succeed." However, since you need to handle failures
anyways, I
think you should remove the comment entirely.

As BOOKE mmu translation needs AS + PID + address,
The infomations we pass to kvmppc here only count in address and set
AS=0, PID=0.
Which indicates that it's a kernel address.

If want to translate user space address, one way is read registers from
kvmppc at first
and then pass the correct AS and PID to translator.
As we don't need to debug guest userspace, for simplicity, I didn't do

Second, (and this isn't an objection but rather a question)
do you have
any better ideas for struct kvm_translation? It only really
makes sense
for x86. We don't need to stick with it.

Hrr.. We need to combine AS, PID and 32-bit addr into 64-bit linear
address. it's not that convenient.
But except that, I am not sure if there is strong requirement to change

BOOK3S KVM has more work in qemu (openbios, vga etc.),
Maybe Alex has some suggestion?

What does that do again? Enable userspace to do EA to PA translation?

IMHO userspace should do the translation and do an ioctl to fetch the required information (soft TLB cache / SLB / SDR1) so we can reuse the existing qemu infrastructure.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]