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Message-Id: <20210430123822.13825-27-brijesh.singh@amd.com>
Date: Fri, 30 Apr 2021 07:38:11 -0500
From: Brijesh Singh <brijesh.singh@....com>
To: x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: tglx@...utronix.de, bp@...en8.de, jroedel@...e.de,
thomas.lendacky@....com, pbonzini@...hat.com, mingo@...hat.com,
dave.hansen@...el.com, rientjes@...gle.com, seanjc@...gle.com,
peterz@...radead.org, hpa@...or.com, tony.luck@...el.com,
Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH Part2 RFC v2 26/37] KVM: X86: Add kvm_x86_ops to get the max page level for the TDP
When running an SEV-SNP VM, the sPA used to index the RMP entry is
obtained through the TDP translation (gva->gpa->spa). The TDP page
level is checked against the page level programmed in the RMP entry.
If the page level does not match, then it will cause a nested page
fault with the RMP bit set to indicate the RMP violation.
To keep the TDP and RMP page level's in sync, the KVM fault handle
kvm_handle_page_fault() will call get_tdp_max_page_level() to get
the maximum allowed page level so that it can limit the TDP level.
In the case of SEV-SNP guest, the get_tdp_max_page_level() will consult
the RMP table to compute the maximum allowed page level for a given
GPA.
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/mmu/mmu.c | 6 ++++--
arch/x86/kvm/svm/sev.c | 20 ++++++++++++++++++++
arch/x86/kvm/svm/svm.c | 1 +
arch/x86/kvm/svm/svm.h | 1 +
arch/x86/kvm/vmx/vmx.c | 8 ++++++++
6 files changed, 35 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 71e79a1998ad..88033147a6bf 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1382,6 +1382,7 @@ struct kvm_x86_ops {
void (*vcpu_deliver_sipi_vector)(struct kvm_vcpu *vcpu, u8 vector);
void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu);
+ int (*get_tdp_max_page_level)(struct kvm_vcpu *vcpu, gpa_t gpa, int max_level);
};
struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 930ac8a7e7c9..fe2c5a704a16 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3781,11 +3781,13 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa,
u32 error_code, bool prefault)
{
+ int max_level = kvm_x86_ops.get_tdp_max_page_level(vcpu, gpa, PG_LEVEL_2M);
+
pgprintk("%s: gva %lx error %x\n", __func__, gpa, error_code);
/* This path builds a PAE pagetable, we can map 2mb pages at maximum. */
return direct_page_fault(vcpu, gpa & PAGE_MASK, error_code, prefault,
- PG_LEVEL_2M, false);
+ max_level, false);
}
int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
@@ -3826,7 +3828,7 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
{
int max_level;
- for (max_level = KVM_MAX_HUGEPAGE_LEVEL;
+ for (max_level = kvm_x86_ops.get_tdp_max_page_level(vcpu, gpa, KVM_MAX_HUGEPAGE_LEVEL);
max_level > PG_LEVEL_4K;
max_level--) {
int page_num = KVM_PAGES_PER_HPAGE(max_level);
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 7da24b3600c4..3203abbd22f3 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3188,3 +3188,23 @@ struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu)
return pfn_to_page(pfn);
}
+
+int sev_get_tdp_max_page_level(struct kvm_vcpu *vcpu, gpa_t gpa, int max_level)
+{
+ struct rmpentry *e;
+ kvm_pfn_t pfn;
+ int level;
+
+ if (!sev_snp_guest(vcpu->kvm))
+ return max_level;
+
+ pfn = gfn_to_pfn(vcpu->kvm, gpa_to_gfn(gpa));
+ if (is_error_noslot_pfn(pfn))
+ return max_level;
+
+ e = snp_lookup_page_in_rmptable(pfn_to_page(pfn), &level);
+ if (unlikely(!e))
+ return max_level;
+
+ return min_t(uint32_t, level, max_level);
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1b9091d750fc..81a83a7c1229 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4617,6 +4617,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector,
.alloc_apic_backing_page = svm_alloc_apic_backing_page,
+ .get_tdp_max_page_level = sev_get_tdp_max_page_level,
};
static struct kvm_x86_init_ops svm_init_ops __initdata = {
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a870bbb64ce7..cf9f0e6c6827 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -567,6 +567,7 @@ void sev_es_create_vcpu(struct vcpu_svm *svm);
void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector);
void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu);
struct page *snp_safe_alloc_page(struct kvm_vcpu *vcpu);
+int sev_get_tdp_max_page_level(struct kvm_vcpu *vcpu, gpa_t gpa, int max_level);
/* vmenter.S */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 10b610fc7bbc..6733f1557016 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7670,6 +7670,12 @@ static bool vmx_check_apicv_inhibit_reasons(ulong bit)
return supported & BIT(bit);
}
+
+static int vmx_get_tdp_max_page_level(struct kvm_vcpu *vcpu, gpa_t gpa, int max_level)
+{
+ return max_level;
+}
+
static struct kvm_x86_ops vmx_x86_ops __initdata = {
.hardware_unsetup = hardware_unsetup,
@@ -7800,6 +7806,8 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
.complete_emulated_msr = kvm_complete_insn_gp,
.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
+
+ .get_tdp_max_page_level = vmx_get_tdp_max_page_level,
};
static __init int hardware_setup(void)
--
2.17.1
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