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KVM: x86: add SMM to the MMU role, support SMRAM address space

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This is now very simple to do.  The only interesting part is a simple
trick to find the right memslot in gfn_to_rmap, retrieving the address
space from the spte role word.  The same trick is used in the auditing
code.

The comment on top of union kvm_mmu_page_role has been stale forever,
so remove it.  Speaking of stale code, remove pad_for_nice_hex_output
too: it was splitting the "access" bitfield across two bytes and thus
had effectively turned into pad_for_ugly_hex_output.

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2015-05-18 15:03:39 +02:00
parent 9da0e4d5ac
commit 699023e239
5 changed files with 42 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Documentation/virtual/kvm/mmu.txt
View File

@ -173,6 +173,12 @@ Shadow pages contain the following information:
Contains the value of cr4.smap && !cr0.wp for which the page is valid
(pages for which this is true are different from other pages; see the
treatment of cr0.wp=0 below).
role.smm:
Is 1 if the page is valid in system management mode. This field
determines which of the kvm_memslots array was used to build this
shadow page; it is also used to go back from a struct kvm_mmu_page
to a memslot, through the kvm_memslots_for_spte_role macro and
__gfn_to_memslot.
gfn:
Either the guest page table containing the translations shadowed by this
page, or the base page frame for linear translations. See role.direct.

26
arch/x86/include/asm/kvm_host.h
View File

@ -184,23 +184,12 @@ struct kvm_mmu_memory_cache {
void *objects[KVM_NR_MEM_OBJS];
};
/*
* kvm_mmu_page_role, below, is defined as:
*
* bits 0:3 - total guest paging levels (2-4, or zero for real mode)
* bits 4:7 - page table level for this shadow (1-4)
* bits 8:9 - page table quadrant for 2-level guests
* bit 16 - direct mapping of virtual to physical mapping at gfn
* used for real mode and two-dimensional paging
* bits 17:19 - common access permissions for all ptes in this shadow page
*/
union kvm_mmu_page_role {
unsigned word;
struct {
unsigned level:4;
unsigned cr4_pae:1;
unsigned quadrant:2;
unsigned pad_for_nice_hex_output:6;
unsigned direct:1;
unsigned access:3;
unsigned invalid:1;
@ -208,6 +197,15 @@ union kvm_mmu_page_role {
unsigned cr0_wp:1;
unsigned smep_andnot_wp:1;
unsigned smap_andnot_wp:1;
unsigned :8;
/*
* This is left at the top of the word so that
* kvm_memslots_for_spte_role can extract it with a
* simple shift. While there is room, give it a whole
* byte so it is also faster to load it from memory.
*/
unsigned smm:8;
};
};
@ -1120,6 +1118,12 @@ enum {
#define HF_SMM_MASK (1 << 6)
#define HF_SMM_INSIDE_NMI_MASK (1 << 7)
#define __KVM_VCPU_MULTIPLE_ADDRESS_SPACE
#define KVM_ADDRESS_SPACE_NUM 2
#define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
#define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)
/*
* Hardware virtualization extension instructions may fault if a
* reboot turns off virtualization while processes are running.

15
arch/x86/kvm/mmu.c
View File

@ -806,13 +806,15 @@ static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *slot;
struct kvm_lpage_info *linfo;
gfn_t gfn;
int i;
gfn = sp->gfn;
slot = gfn_to_memslot(kvm, gfn);
slots = kvm_memslots_for_spte_role(kvm, sp->role);
slot = __gfn_to_memslot(slots, gfn);
for (i = PT_DIRECTORY_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
linfo = lpage_info_slot(gfn, slot, i);
linfo->write_count += 1;
@ -822,13 +824,15 @@ static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *slot;
struct kvm_lpage_info *linfo;
gfn_t gfn;
int i;
gfn = sp->gfn;
slot = gfn_to_memslot(kvm, gfn);
slots = kvm_memslots_for_spte_role(kvm, sp->role);
slot = __gfn_to_memslot(slots, gfn);
for (i = PT_DIRECTORY_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
linfo = lpage_info_slot(gfn, slot, i);
linfo->write_count -= 1;
@ -1045,9 +1049,11 @@ static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
*/
static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, struct kvm_mmu_page *sp)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *slot;
slot = gfn_to_memslot(kvm, gfn);
slots = kvm_memslots_for_spte_role(kvm, sp->role);
slot = __gfn_to_memslot(slots, gfn);
return __gfn_to_rmap(gfn, sp->role.level, slot);
}
@ -3924,6 +3930,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
struct kvm_mmu *context = &vcpu->arch.mmu;
context->base_role.word = 0;
context->base_role.smm = is_smm(vcpu);
context->page_fault = tdp_page_fault;
context->sync_page = nonpaging_sync_page;
context->invlpg = nonpaging_invlpg;
@ -3985,6 +3992,7 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu)
= smep && !is_write_protection(vcpu);
context->base_role.smap_andnot_wp
= smap && !is_write_protection(vcpu);
context->base_role.smm = is_smm(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
@ -4268,6 +4276,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
mask.nxe = 1;
mask.smep_andnot_wp = 1;
mask.smap_andnot_wp = 1;
mask.smm = 1;
/*
* If we don't have indirect shadow pages, it means no page is

10
arch/x86/kvm/mmu_audit.c
View File

@ -131,12 +131,16 @@ static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
unsigned long *rmapp;
struct kvm_mmu_page *rev_sp;
struct kvm_memslots *slots;
struct kvm_memory_slot *slot;
gfn_t gfn;
rev_sp = page_header(__pa(sptep));
gfn = kvm_mmu_page_get_gfn(rev_sp, sptep - rev_sp->spt);
if (!gfn_to_memslot(kvm, gfn)) {
slots = kvm_memslots_for_spte_role(kvm, rev_sp->role);
slot = __gfn_to_memslot(slots, gfn);
if (!slot) {
if (!__ratelimit(&ratelimit_state))
return;
audit_printk(kvm, "no memslot for gfn %llx\n", gfn);
@ -146,7 +150,7 @@ static void inspect_spte_has_rmap(struct kvm *kvm, u64 *sptep)
return;
}
rmapp = gfn_to_rmap(kvm, gfn, rev_sp);
rmapp = __gfn_to_rmap(gfn, rev_sp->role.level, slot);
if (!*rmapp) {
if (!__ratelimit(&ratelimit_state))
return;
@ -197,7 +201,7 @@ static void audit_write_protection(struct kvm *kvm, struct kvm_mmu_page *sp)
if (sp->role.direct || sp->unsync || sp->role.invalid)
return;
slots = kvm_memslots(kvm);
slots = kvm_memslots_for_spte_role(kvm, sp->role);
slot = __gfn_to_memslot(slots, sp->gfn);
rmapp = __gfn_to_rmap(sp->gfn, PT_PAGE_TABLE_LEVEL, slot);

2
arch/x86/kvm/x86.c
View File

@ -5490,6 +5490,8 @@ static void kvm_smm_changed(struct kvm_vcpu *vcpu)
kvm_make_request(KVM_REQ_EVENT, vcpu);
}
}
kvm_mmu_reset_context(vcpu);
}
static void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags)