[PATCH v2 0/3] KVM: Fix and clean up kvm_vcpu_map[_readonly]() usages

[PATCH v2 0/3] KVM: Fix and clean up kvm_vcpu_map[_readonly]() usages

[Peter Fang]

kvm_vcpu_map() and kvm_vcpu_map_readonly() are declared to take a gpa_t
in kvm_host.h when they're supposed to take a gfn_t. First fix the
function prototypes, and then refactor them to correctly take a gpa_t,
reducing boilerplate gpa->gfn conversions at all call sites.

No actual harm has been done yet as all of the call sites are correctly
passing in a gfn.

No functional change intended. All changes are compile-tested on x86 and
ppc, which are the current users of these APIs.

---

v1 -> v2:
  - Rebased on top of latest kvm.git#master
  - As suggested by Yosry, refactor the APIs to reduce boilerplate code
    at call sites

v1: https://lore.kernel.org/kvm/20260325092001.613025-1-peter.fang@intel.com/

Peter Fang (3):
  KVM: Fix kvm_vcpu_map[_readonly]() function prototypes
  KVM: Move page mapping/unmapping APIs in kvm_host.h
  KVM: Take gpa_t in kvm_vcpu_map[_readonly]()

 arch/powerpc/kvm/book3s_pr.c |  2 +-
 arch/x86/kvm/svm/nested.c    |  4 ++--
 arch/x86/kvm/svm/sev.c       |  2 +-
 arch/x86/kvm/svm/svm.c       |  8 +++----
 arch/x86/kvm/vmx/nested.c    | 11 ++++-----
 include/linux/kvm_host.h     | 46 ++++++++++++++++++------------------
 6 files changed, 36 insertions(+), 37 deletions(-)


base-commit: df83746075778958954aa0460cca55f4b3fc9c02
-- 
2.53.0

[PATCH v2 1/3] KVM: Fix kvm_vcpu_map[_readonly]() function prototypes

[Peter Fang]

kvm_vcpu_map() and kvm_vcpu_map_readonly() should take a gfn instead of
a gpa. This appears to be a result of the original kvm_vcpu_map() being
declared with the wrong function prototype in kvm_host.h, even though
it was correct in the actual implementation in kvm_main.c.

No actual harm has been done yet as all of the call sites are correctly
passing in a gfn. Plus, both gfn_t and gpa_t are typedef'd to u64 so
this change shouldn't have any functional impact.

Compile-tested on x86 and ppc, which are the current users of these
interfaces.

Fixes: e45adf665a53 ("KVM: Introduce a new guest mapping API")
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Peter Fang <peter.fang@intel.com>
---
 include/linux/kvm_host.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6b76e7a6f4c2..4e3bea92a06b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1382,20 +1382,20 @@ void mark_page_dirty_in_slot(struct kvm *kvm, const struct kvm_memory_slot *mems
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
 void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
 
-int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_host_map *map,
+int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
 		   bool writable);
 void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map);
 
-static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa,
+static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn,
 			       struct kvm_host_map *map)
 {
-	return __kvm_vcpu_map(vcpu, gpa, map, true);
+	return __kvm_vcpu_map(vcpu, gfn, map, true);
 }
 
-static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gpa_t gpa,
+static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gfn_t gfn,
 					struct kvm_host_map *map)
 {
-	return __kvm_vcpu_map(vcpu, gpa, map, false);
+	return __kvm_vcpu_map(vcpu, gfn, map, false);
 }
 
 static inline void kvm_vcpu_map_mark_dirty(struct kvm_vcpu *vcpu,
-- 
2.53.0

[PATCH v2 2/3] KVM: Move page mapping/unmapping APIs in kvm_host.h

[Peter Fang]

Move kvm_vcpu_map*() and kvm_vcpu_unmap() so that a subsequent refactor
can use gpa_to_gfn() without a forward declaration.

No functional change intended.

Signed-off-by: Peter Fang <peter.fang@intel.com>
---
 include/linux/kvm_host.h | 46 ++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4e3bea92a06b..484378cfdcc0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1382,29 +1382,6 @@ void mark_page_dirty_in_slot(struct kvm *kvm, const struct kvm_memory_slot *mems
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
 void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn);
 
-int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
-		   bool writable);
-void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map);
-
-static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn,
-			       struct kvm_host_map *map)
-{
-	return __kvm_vcpu_map(vcpu, gfn, map, true);
-}
-
-static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gfn_t gfn,
-					struct kvm_host_map *map)
-{
-	return __kvm_vcpu_map(vcpu, gfn, map, false);
-}
-
-static inline void kvm_vcpu_map_mark_dirty(struct kvm_vcpu *vcpu,
-					   struct kvm_host_map *map)
-{
-	if (kvm_vcpu_mapped(map))
-		kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
-}
-
 unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn);
 unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable);
 int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, int offset,
@@ -1916,6 +1893,29 @@ static inline hpa_t pfn_to_hpa(kvm_pfn_t pfn)
 	return (hpa_t)pfn << PAGE_SHIFT;
 }
 
+int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
+		   bool writable);
+void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map);
+
+static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn,
+			       struct kvm_host_map *map)
+{
+	return __kvm_vcpu_map(vcpu, gfn, map, true);
+}
+
+static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gfn_t gfn,
+					struct kvm_host_map *map)
+{
+	return __kvm_vcpu_map(vcpu, gfn, map, false);
+}
+
+static inline void kvm_vcpu_map_mark_dirty(struct kvm_vcpu *vcpu,
+					   struct kvm_host_map *map)
+{
+	if (kvm_vcpu_mapped(map))
+		kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
+}
+
 static inline bool kvm_is_gpa_in_memslot(struct kvm *kvm, gpa_t gpa)
 {
 	unsigned long hva = gfn_to_hva(kvm, gpa_to_gfn(gpa));
-- 
2.53.0

[PATCH v2 3/3] KVM: Take gpa_t in kvm_vcpu_map[_readonly]()

[Peter Fang]

Move the conversion from a gpa_t to a gfn_t into kvm_vcpu_map() and
kvm_vcpu_map_readonly() so that they take a gpa_t directly, reducing
boilerplate at call sites.

__kvm_vcpu_map() still takes a gfn_t because guest page mapping is
fundamentally GFN-based.

No functional change intended.

Compile-tested on x86 and ppc, which are the current users of these
interfaces.

Suggested-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Peter Fang <peter.fang@intel.com>
---
 arch/powerpc/kvm/book3s_pr.c |  2 +-
 arch/x86/kvm/svm/nested.c    |  4 ++--
 arch/x86/kvm/svm/sev.c       |  2 +-
 arch/x86/kvm/svm/svm.c       |  8 ++++----
 arch/x86/kvm/vmx/nested.c    | 11 +++++------
 include/linux/kvm_host.h     |  8 ++++----
 6 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 2ba2dd26a7ea..45dea4064618 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -644,7 +644,7 @@ static void kvmppc_patch_dcbz(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
 	u32 *page;
 	int i, r;
 
-	r = kvm_vcpu_map(vcpu, pte->raddr >> PAGE_SHIFT, &map);
+	r = kvm_vcpu_map(vcpu, pte->raddr, &map);
 	if (r)
 		return;
 
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index b36c33255bed..f168b54828bb 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1019,7 +1019,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 	}
 
 	vmcb12_gpa = svm->vmcb->save.rax;
-	ret = kvm_vcpu_map(vcpu, gpa_to_gfn(vmcb12_gpa), &map);
+	ret = kvm_vcpu_map(vcpu, vmcb12_gpa, &map);
 	if (ret == -EINVAL) {
 		kvm_inject_gp(vcpu, 0);
 		return 1;
@@ -1134,7 +1134,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	struct kvm_host_map map;
 	int rc;
 
-	rc = kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.vmcb12_gpa), &map);
+	rc = kvm_vcpu_map(vcpu, svm->nested.vmcb12_gpa, &map);
 	if (rc) {
 		if (rc == -EINVAL)
 			kvm_inject_gp(vcpu, 0);
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 3f9c1aa39a0a..524607bb8cc2 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4405,7 +4405,7 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 		return 1;
 	}
 
-	if (kvm_vcpu_map(vcpu, ghcb_gpa >> PAGE_SHIFT, &svm->sev_es.ghcb_map)) {
+	if (kvm_vcpu_map(vcpu, ghcb_gpa, &svm->sev_es.ghcb_map)) {
 		/* Unable to map GHCB from guest */
 		vcpu_unimpl(vcpu, "vmgexit: error mapping GHCB [%#llx] from guest\n",
 			    ghcb_gpa);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e6477affac9a..823c6a6f3594 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2159,7 +2159,7 @@ static int vmload_vmsave_interception(struct kvm_vcpu *vcpu, bool vmload)
 	if (nested_svm_check_permissions(vcpu))
 		return 1;
 
-	ret = kvm_vcpu_map(vcpu, gpa_to_gfn(svm->vmcb->save.rax), &map);
+	ret = kvm_vcpu_map(vcpu, svm->vmcb->save.rax, &map);
 	if (ret) {
 		if (ret == -EINVAL)
 			kvm_inject_gp(vcpu, 0);
@@ -4820,7 +4820,7 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)
 	 * that, see svm_prepare_switch_to_guest()) which must be
 	 * preserved.
 	 */
-	if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), &map_save))
+	if (kvm_vcpu_map(vcpu, svm->nested.hsave_msr, &map_save))
 		return 1;
 
 	BUILD_BUG_ON(offsetof(struct vmcb, save) != 0x400);
@@ -4854,11 +4854,11 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)
 	if (!(smram64->efer & EFER_SVME))
 		return 1;
 
-	if (kvm_vcpu_map(vcpu, gpa_to_gfn(smram64->svm_guest_vmcb_gpa), &map))
+	if (kvm_vcpu_map(vcpu, smram64->svm_guest_vmcb_gpa, &map))
 		return 1;
 
 	ret = 1;
-	if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), &map_save))
+	if (kvm_vcpu_map(vcpu, svm->nested.hsave_msr, &map_save))
 		goto unmap_map;
 
 	if (svm_allocate_nested(svm))
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 937aeb474af7..ee3ff76a8678 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -696,7 +696,7 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
 			return true;
 	}
 
-	if (kvm_vcpu_map_readonly(vcpu, gpa_to_gfn(vmcs12->msr_bitmap), &map))
+	if (kvm_vcpu_map_readonly(vcpu, vmcs12->msr_bitmap, &map))
 		return false;
 
 	msr_bitmap_l1 = (unsigned long *)map.hva;
@@ -2138,8 +2138,7 @@ static enum nested_evmptrld_status nested_vmx_handle_enlightened_vmptrld(
 
 		nested_release_evmcs(vcpu);
 
-		if (kvm_vcpu_map(vcpu, gpa_to_gfn(evmcs_gpa),
-				 &vmx->nested.hv_evmcs_map))
+		if (kvm_vcpu_map(vcpu, evmcs_gpa, &vmx->nested.hv_evmcs_map))
 			return EVMPTRLD_ERROR;
 
 		vmx->nested.hv_evmcs = vmx->nested.hv_evmcs_map.hva;
@@ -3437,7 +3436,7 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
 	if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
 		map = &vmx->nested.apic_access_page_map;
 
-		if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->apic_access_addr), map)) {
+		if (!kvm_vcpu_map(vcpu, vmcs12->apic_access_addr, map)) {
 			vmcs_write64(APIC_ACCESS_ADDR, pfn_to_hpa(map->pfn));
 		} else {
 			pr_debug_ratelimited("%s: no backing for APIC-access address in vmcs12\n",
@@ -3453,7 +3452,7 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
 	if (nested_cpu_has(vmcs12, CPU_BASED_TPR_SHADOW)) {
 		map = &vmx->nested.virtual_apic_map;
 
-		if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->virtual_apic_page_addr), map)) {
+		if (!kvm_vcpu_map(vcpu, vmcs12->virtual_apic_page_addr, map)) {
 			vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, pfn_to_hpa(map->pfn));
 		} else if (nested_cpu_has(vmcs12, CPU_BASED_CR8_LOAD_EXITING) &&
 		           nested_cpu_has(vmcs12, CPU_BASED_CR8_STORE_EXITING) &&
@@ -3479,7 +3478,7 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
 	if (nested_cpu_has_posted_intr(vmcs12)) {
 		map = &vmx->nested.pi_desc_map;
 
-		if (!kvm_vcpu_map(vcpu, gpa_to_gfn(vmcs12->posted_intr_desc_addr), map)) {
+		if (!kvm_vcpu_map(vcpu, vmcs12->posted_intr_desc_addr, map)) {
 			vmx->nested.pi_desc =
 				(struct pi_desc *)(((void *)map->hva) +
 				offset_in_page(vmcs12->posted_intr_desc_addr));
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 484378cfdcc0..893a8c76a665 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1897,16 +1897,16 @@ int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
 		   bool writable);
 void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map);
 
-static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn,
+static inline int kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa,
 			       struct kvm_host_map *map)
 {
-	return __kvm_vcpu_map(vcpu, gfn, map, true);
+	return __kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), map, true);
 }
 
-static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gfn_t gfn,
+static inline int kvm_vcpu_map_readonly(struct kvm_vcpu *vcpu, gpa_t gpa,
 					struct kvm_host_map *map)
 {
-	return __kvm_vcpu_map(vcpu, gfn, map, false);
+	return __kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), map, false);
 }
 
 static inline void kvm_vcpu_map_mark_dirty(struct kvm_vcpu *vcpu,
-- 
2.53.0