Re: [PATCH] Add ability to drop pages through testdev

Gleb Natapov
2010-12-29T10:03:05Z

On Wed, Dec 29, 2010 at 11:58:31AM +0200, Avi Kivity wrote:
> On 12/29/2010 11:55 AM, Gleb Natapov wrote:
> >On Wed, Dec 29, 2010 at 11:50:48AM +0200, Avi Kivity wrote:
> >> On 12/22/2010 05:18 PM, Gleb Natapov wrote:
> >> >Signed-off-by: Gleb Natapov<gleb@redhat.com>
> >> >diff --git a/hw/testdev.c b/hw/testdev.c
> >> >index d1abf59..29df385 100644
> >> >--- a/hw/testdev.c
> >> >+++ b/hw/testdev.c
> >> >@@ -1,3 +1,4 @@
> >> >+#include<sys/mman.h>
> >> > #include "hw.h"
> >> > #include "qdev.h"
> >> > #include "isa.h"
> >> >@@ -46,6 +47,16 @@ static uint32_t test_device_ioport_read(void *opaque, uint32_t addr)
> >> > return test_device_ioport_data;
> >> > }
> >> >
> >> >+static void test_device_flush_page(void *opaque, uint32_t addr, uint32_t data)
> >> >+{
> >> >+ target_phys_addr_t len = 4096;
> >> >+ void *a = cpu_physical_memory_map(data& ~0xffful,&len, 0);
> >> >+
> >> >+ mprotect(a, 4096, PROT_NONE);
> >> >+ mprotect(a, 4096, PROT_READ|PROT_WRITE);
> >> >+ cpu_physical_memory_unmap(a, len, 0, 0);
> >> >+}
> >> >+
> >>
> >> Icky. This is much better done through the api tests. Applied it
> >> so as not to spoil all the effort.
> >>
> >How would you do that there?
>
> Set up all the state using the KVM_SET_REGS family, pointing to the
> instruction you want to test, and KVM_RUN that. You can even queue
> exceptions and interrupts for complicated cases.
>
I mean how do you drop a page from shadow/ept tables? Wouldn't you have
to do the same trick there?

--
Gleb.