On 7/14/22 17:37, Sean Christopherson wrote:
Restrict get_mt_mask() to a u8 and reintroduce using a RET0 static_call
for the SVM implementation. EPT stores the memtype information in the
lower 8 bits (bits 6:3 to be precise), and even returns a shifted u8
without an explicit cast to a larger type; there's no need to return a
full u64.
Note, RET0 doesn't play nice with a u64 return on 32-bit kernels, see
commit bf07be36cd88 ("KVM: x86: do not use KVM_X86_OP_OPTIONAL_RET0 for
get_mt_mask").
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Doh, that's obvious. Queued, thanks.
Paolo
---
arch/x86/include/asm/kvm-x86-ops.h | 2 +-
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/svm/svm.c | 6 ------
arch/x86/kvm/vmx/vmx.c | 2 +-
4 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 6f2f1affbb78..51f777071584 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -88,7 +88,7 @@ KVM_X86_OP(deliver_interrupt)
KVM_X86_OP_OPTIONAL(sync_pir_to_irr)
KVM_X86_OP_OPTIONAL_RET0(set_tss_addr)
KVM_X86_OP_OPTIONAL_RET0(set_identity_map_addr)
-KVM_X86_OP(get_mt_mask)
+KVM_X86_OP_OPTIONAL_RET0(get_mt_mask)
KVM_X86_OP(load_mmu_pgd)
KVM_X86_OP(has_wbinvd_exit)
KVM_X86_OP(get_l2_tsc_offset)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index de5a149d0971..fa4b2392fba0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1546,7 +1546,7 @@ struct kvm_x86_ops {
int (*sync_pir_to_irr)(struct kvm_vcpu *vcpu);
int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
int (*set_identity_map_addr)(struct kvm *kvm, u64 ident_addr);
- u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
+ u8 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa,
int root_level);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 37ce061dfc76..19af6dacfc5b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4158,11 +4158,6 @@ static bool svm_has_emulated_msr(struct kvm *kvm, u32 index)
return true;
}
-static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
-{
- return 0;
-}
-
static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -4814,7 +4809,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.check_apicv_inhibit_reasons = avic_check_apicv_inhibit_reasons,
.apicv_post_state_restore = avic_apicv_post_state_restore,
- .get_mt_mask = svm_get_mt_mask,
.get_exit_info = svm_get_exit_info,
.vcpu_after_set_cpuid = svm_vcpu_after_set_cpuid,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c30115b9cb33..c895a3b6824d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7352,7 +7352,7 @@ static int __init vmx_check_processor_compat(void)
return 0;
}
-static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
+static u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
{
u8 cache;
base-commit: b9b71f43683ae9d76b0989249607bbe8c9eb6c5c
