xen: implement Xen write_msr operation
64-bit uses MSRs for important things like the base for fs and gs-prefixed addresses. It's more efficient to use a hypercall to update these, rather than go via the trap and emulate path. Other MSR writes are just passed through; in an unprivileged domain they do nothing, but it might be useful later. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
parent
bf18bf94dc
commit
1153968a48
|
@ -41,6 +41,7 @@
|
|||
#include <asm/xen/hypervisor.h>
|
||||
#include <asm/fixmap.h>
|
||||
#include <asm/processor.h>
|
||||
#include <asm/msr-index.h>
|
||||
#include <asm/setup.h>
|
||||
#include <asm/desc.h>
|
||||
#include <asm/pgtable.h>
|
||||
|
@ -777,6 +778,34 @@ static void xen_write_cr3(unsigned long cr3)
|
|||
xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
|
||||
}
|
||||
|
||||
static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = 0;
|
||||
|
||||
switch(msr) {
|
||||
#ifdef CONFIG_X86_64
|
||||
unsigned which;
|
||||
u64 base;
|
||||
|
||||
case MSR_FS_BASE: which = SEGBASE_FS; goto set;
|
||||
case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set;
|
||||
case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set;
|
||||
|
||||
set:
|
||||
base = ((u64)high << 32) | low;
|
||||
if (HYPERVISOR_set_segment_base(which, base) != 0)
|
||||
ret = -EFAULT;
|
||||
break;
|
||||
#endif
|
||||
default:
|
||||
ret = native_write_msr_safe(msr, low, high);
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Early in boot, while setting up the initial pagetable, assume
|
||||
everything is pinned. */
|
||||
static __init void xen_alloc_pte_init(struct mm_struct *mm, u32 pfn)
|
||||
|
@ -1165,7 +1194,7 @@ static const struct pv_cpu_ops xen_cpu_ops __initdata = {
|
|||
.wbinvd = native_wbinvd,
|
||||
|
||||
.read_msr = native_read_msr_safe,
|
||||
.write_msr = native_write_msr_safe,
|
||||
.write_msr = xen_write_msr_safe,
|
||||
.read_tsc = native_read_tsc,
|
||||
.read_pmc = native_read_pmc,
|
||||
|
||||
|
|
Loading…
Reference in a new issue