Re: [PATCH v5 07/13] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page
On Wed, 2019-01-23 at 12:57 -0500, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 09, 2019 at 10:42:07AM +0100, KarimAllah Ahmed wrote:
> >
> > Use kvm_vcpu_map when mapping the virtual APIC page since using
> > kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
> > a "struct page".
> >
> > One additional semantic change is that the virtual host mapping lifecycle
> > has changed a bit. It now has the same lifetime of the pinning of the
> > virtual APIC page on the host side.
>
> Could you expand a bit on the 'same lifetime .. on the host side' to be
> obvious for folks what exactly the semantic is?
>
> And how does this ring with this comment:
> >
> >
> > Signed-off-by: KarimAllah Ahmed
> > ---
> > v4 -> v5:
> > - unmap with dirty flag
> >
> > v1 -> v2:
> > - Do not change the lifecycle of the mapping (pbonzini)
>
> .. Where Paolo does not want the semantics of the mapping to be changed?
>
> Code wise feel free to smack my Reviewed-by on it, but obviously the
> question on the above comment needs to be resolved.
Ah, right. So there was two life-cycle changes:
1- Lazily unmap the mapping and only do it on: a) release b) if the gfn is
different. This was done as an optimization (i.e. cache of a single entry).
This is the first life-cycle change that Paolo asked me to do seperately and
suggested to create a PFN cache instead. This has indeed been dropped
between v1 -> v2 switch.
2- The life-cycle change now is the fact that the kvm_vcpu_map interface does:
a) map to a virtual address b) translate a gfn to a pfn.
The original code was doing the kmap in one location and the gfn_to_page in
another. Using kvm_vcpu_map means that both kmap+gfn_to_page will be tied
together and will not be done seperately. So far no one complained about
this one so I kept it :D
>
> Thank you.
>
> >
> > - Use pfn_to_hpa instead of gfn_to_gpa
> > ---
> > arch/x86/kvm/vmx/nested.c | 32 +++-
> > arch/x86/kvm/vmx/vmx.c| 5 ++---
> > arch/x86/kvm/vmx/vmx.h| 2 +-
> > 3 files changed, 14 insertions(+), 25 deletions(-)
> >
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index 4127ad9..dcff99d 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -229,10 +229,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
> > kvm_release_page_dirty(vmx->nested.apic_access_page);
> > vmx->nested.apic_access_page = NULL;
> > }
> > - if (vmx->nested.virtual_apic_page) {
> > - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> > - vmx->nested.virtual_apic_page = NULL;
> > - }
> > + kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
> > if (vmx->nested.pi_desc_page) {
> > kunmap(vmx->nested.pi_desc_page);
> > kvm_release_page_dirty(vmx->nested.pi_desc_page);
> > @@ -2817,6 +2814,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
> > *vcpu)
> > {
> > struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
> > struct vcpu_vmx *vmx = to_vmx(vcpu);
> > + struct kvm_host_map *map;
> > struct page *page;
> > u64 hpa;
> >
> > @@ -2849,11 +2847,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
> > *vcpu)
> > }
> >
> > if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
> > - if (vmx->nested.virtual_apic_page) { /* shouldn't happen */
> > - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> > - vmx->nested.virtual_apic_page = NULL;
> > - }
> > - page = kvm_vcpu_gpa_to_page(vcpu,
> > vmcs12->virtual_apic_page_addr);
> > + map = &vmx->nested.virtual_apic_map;
> >
> > /*
> > * If translation failed, VM entry will fail because
> > @@ -2868,11 +2862,9 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
> > *vcpu)
> > * control. But such a configuration is useless, so
> > * let's keep the code simple.
> > */
> > - if (!is_error_page(page)) {
> > - vmx->nested.virtual_apic_page = page;
> > - hpa = page_to_phys(vmx->nested.virtual_apic_page);
> > - vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa);
> > - }
> > + if (!kvm_vcpu_map(vcpu,
> > gpa_to_gfn(vmcs12->virtual_apic_page_addr), map))
> > + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR,
> > pfn_to_hpa(map->pfn));
> > +
> > }
> >
> > if (nested_cpu_has_posted_intr(vmcs12)) {
> > @@ -3279,11 +3271,12 @@ static void
> > vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)
> >
> > max_irr = find_last_bit((unsigned long *)vmx->nested.pi_desc->pir, 256);
> > if (max_irr != 256) {
> > - vapic_page = kmap(vmx->nested.virtual_apic_page);
> > + vapic_page = vmx->nested.virtual_apic_map.hva;
> > + if (!vapic_page)
> > + return;
> > +
Re: [PATCH v5 07/13] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page
On Wed, Jan 09, 2019 at 10:42:07AM +0100, KarimAllah Ahmed wrote:
> Use kvm_vcpu_map when mapping the virtual APIC page since using
> kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
> a "struct page".
>
> One additional semantic change is that the virtual host mapping lifecycle
> has changed a bit. It now has the same lifetime of the pinning of the
> virtual APIC page on the host side.
Could you expand a bit on the 'same lifetime .. on the host side' to be
obvious for folks what exactly the semantic is?
And how does this ring with this comment:
>
> Signed-off-by: KarimAllah Ahmed
> ---
> v4 -> v5:
> - unmap with dirty flag
>
> v1 -> v2:
> - Do not change the lifecycle of the mapping (pbonzini)
.. Where Paolo does not want the semantics of the mapping to be changed?
Code wise feel free to smack my Reviewed-by on it, but obviously the
question on the above comment needs to be resolved.
Thank you.
> - Use pfn_to_hpa instead of gfn_to_gpa
> ---
> arch/x86/kvm/vmx/nested.c | 32 +++-
> arch/x86/kvm/vmx/vmx.c| 5 ++---
> arch/x86/kvm/vmx/vmx.h| 2 +-
> 3 files changed, 14 insertions(+), 25 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 4127ad9..dcff99d 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -229,10 +229,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
> kvm_release_page_dirty(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> - if (vmx->nested.virtual_apic_page) {
> - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> - vmx->nested.virtual_apic_page = NULL;
> - }
> + kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
> if (vmx->nested.pi_desc_page) {
> kunmap(vmx->nested.pi_desc_page);
> kvm_release_page_dirty(vmx->nested.pi_desc_page);
> @@ -2817,6 +2814,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
> *vcpu)
> {
> struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
> struct vcpu_vmx *vmx = to_vmx(vcpu);
> + struct kvm_host_map *map;
> struct page *page;
> u64 hpa;
>
> @@ -2849,11 +2847,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
> *vcpu)
> }
>
> if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
> - if (vmx->nested.virtual_apic_page) { /* shouldn't happen */
> - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> - vmx->nested.virtual_apic_page = NULL;
> - }
> - page = kvm_vcpu_gpa_to_page(vcpu,
> vmcs12->virtual_apic_page_addr);
> + map = &vmx->nested.virtual_apic_map;
>
> /*
>* If translation failed, VM entry will fail because
> @@ -2868,11 +2862,9 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
> *vcpu)
>* control. But such a configuration is useless, so
>* let's keep the code simple.
>*/
> - if (!is_error_page(page)) {
> - vmx->nested.virtual_apic_page = page;
> - hpa = page_to_phys(vmx->nested.virtual_apic_page);
> - vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa);
> - }
> + if (!kvm_vcpu_map(vcpu,
> gpa_to_gfn(vmcs12->virtual_apic_page_addr), map))
> + vmcs_write64(VIRTUAL_APIC_PAGE_ADDR,
> pfn_to_hpa(map->pfn));
> +
> }
>
> if (nested_cpu_has_posted_intr(vmcs12)) {
> @@ -3279,11 +3271,12 @@ static void
> vmx_complete_nested_posted_interrupt(struct kvm_vcpu *vcpu)
>
> max_irr = find_last_bit((unsigned long *)vmx->nested.pi_desc->pir, 256);
> if (max_irr != 256) {
> - vapic_page = kmap(vmx->nested.virtual_apic_page);
> + vapic_page = vmx->nested.virtual_apic_map.hva;
> + if (!vapic_page)
> + return;
> +
> __kvm_apic_update_irr(vmx->nested.pi_desc->pir,
> vapic_page, &max_irr);
> - kunmap(vmx->nested.virtual_apic_page);
> -
> status = vmcs_read16(GUEST_INTR_STATUS);
> if ((u8)max_irr > ((u8)status & 0xff)) {
> status &= ~0xff;
> @@ -3917,10 +3910,7 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32
> exit_reason,
> kvm_release_page_dirty(vmx->nested.apic_access_page);
> vmx->nested.apic_access_page = NULL;
> }
> - if (vmx->nested.virtual_apic_page) {
> - kvm_release_page_dirty(vmx->nested.virtual_apic_page);
> - vmx->nested.virtual_apic_page = NULL;
> - }
> + kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
> if (vmx->nested.pi_desc_page) {
> kunmap(vmx->nested.pi_desc_page);
> kvm_release_page_dirty(vmx->nested.pi_desc_page);
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch
[PATCH v5 07/13] KVM/nVMX: Use kvm_vcpu_map when mapping the virtual APIC page
Use kvm_vcpu_map when mapping the virtual APIC page since using
kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
a "struct page".
One additional semantic change is that the virtual host mapping lifecycle
has changed a bit. It now has the same lifetime of the pinning of the
virtual APIC page on the host side.
Signed-off-by: KarimAllah Ahmed
---
v4 -> v5:
- unmap with dirty flag
v1 -> v2:
- Do not change the lifecycle of the mapping (pbonzini)
- Use pfn_to_hpa instead of gfn_to_gpa
---
arch/x86/kvm/vmx/nested.c | 32 +++-
arch/x86/kvm/vmx/vmx.c| 5 ++---
arch/x86/kvm/vmx/vmx.h| 2 +-
3 files changed, 14 insertions(+), 25 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4127ad9..dcff99d 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -229,10 +229,7 @@ static void free_nested(struct kvm_vcpu *vcpu)
kvm_release_page_dirty(vmx->nested.apic_access_page);
vmx->nested.apic_access_page = NULL;
}
- if (vmx->nested.virtual_apic_page) {
- kvm_release_page_dirty(vmx->nested.virtual_apic_page);
- vmx->nested.virtual_apic_page = NULL;
- }
+ kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
if (vmx->nested.pi_desc_page) {
kunmap(vmx->nested.pi_desc_page);
kvm_release_page_dirty(vmx->nested.pi_desc_page);
@@ -2817,6 +2814,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
{
struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
struct vcpu_vmx *vmx = to_vmx(vcpu);
+ struct kvm_host_map *map;
struct page *page;
u64 hpa;
@@ -2849,11 +2847,7 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
*vcpu)
}
if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
- if (vmx->nested.virtual_apic_page) { /* shouldn't happen */
- kvm_release_page_dirty(vmx->nested.virtual_apic_page);
- vmx->nested.virtual_apic_page = NULL;
- }
- page = kvm_vcpu_gpa_to_page(vcpu,
vmcs12->virtual_apic_page_addr);
+ map = &vmx->nested.virtual_apic_map;
/*
* If translation failed, VM entry will fail because
@@ -2868,11 +2862,9 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu
*vcpu)
* control. But such a configuration is useless, so
* let's keep the code simple.
*/
- if (!is_error_page(page)) {
- vmx->nested.virtual_apic_page = page;
- hpa = page_to_phys(vmx->nested.virtual_apic_page);
- vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa);
- }
+ if (!kvm_vcpu_map(vcpu,
gpa_to_gfn(vmcs12->virtual_apic_page_addr), map))
+ vmcs_write64(VIRTUAL_APIC_PAGE_ADDR,
pfn_to_hpa(map->pfn));
+
}
if (nested_cpu_has_posted_intr(vmcs12)) {
@@ -3279,11 +3271,12 @@ static void vmx_complete_nested_posted_interrupt(struct
kvm_vcpu *vcpu)
max_irr = find_last_bit((unsigned long *)vmx->nested.pi_desc->pir, 256);
if (max_irr != 256) {
- vapic_page = kmap(vmx->nested.virtual_apic_page);
+ vapic_page = vmx->nested.virtual_apic_map.hva;
+ if (!vapic_page)
+ return;
+
__kvm_apic_update_irr(vmx->nested.pi_desc->pir,
vapic_page, &max_irr);
- kunmap(vmx->nested.virtual_apic_page);
-
status = vmcs_read16(GUEST_INTR_STATUS);
if ((u8)max_irr > ((u8)status & 0xff)) {
status &= ~0xff;
@@ -3917,10 +3910,7 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32
exit_reason,
kvm_release_page_dirty(vmx->nested.apic_access_page);
vmx->nested.apic_access_page = NULL;
}
- if (vmx->nested.virtual_apic_page) {
- kvm_release_page_dirty(vmx->nested.virtual_apic_page);
- vmx->nested.virtual_apic_page = NULL;
- }
+ kvm_vcpu_unmap(&vmx->nested.virtual_apic_map, true);
if (vmx->nested.pi_desc_page) {
kunmap(vmx->nested.pi_desc_page);
kvm_release_page_dirty(vmx->nested.pi_desc_page);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 71d88df..e13308e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3627,14 +3627,13 @@ static bool vmx_guest_apic_has_interrupt(struct
kvm_vcpu *vcpu)
if (WARN_ON_ONCE(!is_guest_mode(vcpu)) ||
!nested_cpu_has_vid(get_vmcs12(vcpu)) ||
- WARN_ON_ONCE(!vmx->nested.virtual_apic_page))
+ WARN_ON_ONCE(!vmx->nested.virtual_apic_map.gfn))
return false;
rvi = vmx_get_rvi();
- vapic_page = kmap(vmx->nested.virtual_
