From: Oliver Upton <oupton@kernel.org>
To: kvmarm@lists.linux.dev
Cc: Marc Zyngier <maz@kernel.org>, Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Wei-Lin Chang <weilin.chang@arm.com>,
Steffen Eiden <seiden@linux.ibm.com>,
Fuad Tabba <fuad.tabba@linux.dev>,
Leonardo Bras <leo.bras@arm.com>,
Oliver Upton <oupton@kernel.org>
Subject: [PATCH v2 12/28] KVM: arm64: Create helper for stage-1 descriptor updates
Date: Fri, 23 Oct 2026 13:55:54 -0700 [thread overview]
Message-ID: <20261023205610.1044532-13-oupton@kernel.org> (raw)
In-Reply-To: <20261023205610.1044532-1-oupton@kernel.org>
Prepare for FEAT_HAFT support by creating a helper for descriptor
updates to be used for both leaf and table descriptors.
Reviewed-by: Leonardo Bras <leo.bras@arm.com>
Signed-off-by: Oliver Upton <oupton@kernel.org>
---
arch/arm64/kvm/at.c | 56 +++++++++++++++++++++++++--------------------
1 file changed, 31 insertions(+), 25 deletions(-)
diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index dcbe5563baa2..eba51c6e01af 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -453,9 +453,28 @@ static int kvm_read_s1_desc(struct kvm_vcpu *vcpu, u64 pa, u64 *desc,
return 0;
}
-static int kvm_swap_s1_desc(struct kvm_vcpu *vcpu, u64 pa, u64 old, u64 new,
- struct s1_walk_info *wi)
+static int handle_desc_update(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
+ struct s1_walk_step *ws, struct s1_walk_result *wr,
+ struct kvm_walk_access *access)
{
+ u64 old, new;
+ int ret;
+
+ old = new = ws->desc;
+
+ if (wi->ha)
+ new |= PTE_AF;
+
+ if (new == old)
+ return 0;
+
+ if (wi->s2 && !ws->s2_trans.writable) {
+ fail_s1_walk(wr, ESR_ELx_FSC_PERM_L(ws->level), true);
+ return -EPERM;
+ }
+
+ ws->desc = new;
+
if (wi->be) {
old = (__force u64)cpu_to_be64(old);
new = (__force u64)cpu_to_be64(new);
@@ -464,7 +483,12 @@ static int kvm_swap_s1_desc(struct kvm_vcpu *vcpu, u64 pa, u64 old, u64 new,
new = (__force u64)cpu_to_le64(new);
}
- return __kvm_at_swap_desc(vcpu->kvm, pa, old, new);
+ ret = __kvm_at_swap_desc(vcpu->kvm, ws->desc_pa, old, new);
+ if (!ret || ret == -EAGAIN)
+ return ret;
+
+ fail_s1_walk(wr, ESR_ELx_FSC_SEA_TTW(ws->level), false);
+ return ret;
}
static void compute_s1_permissions(struct kvm_vcpu *vcpu,
@@ -474,7 +498,7 @@ static void compute_s1_permissions(struct kvm_vcpu *vcpu,
static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
struct s1_walk_result *wr, struct kvm_walk_access *access)
{
- u64 va_top, va_bottom, baddr, new_desc, va;
+ u64 va_top, va_bottom, baddr, va;
struct s1_walk_step ws = {};
int stride, ret;
@@ -544,8 +568,6 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
return ret;
}
- new_desc = ws.desc;
-
/* Invalid descriptor */
if (!(ws.desc & BIT(0)))
goto transfault;
@@ -615,25 +637,9 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
compute_s1_permissions(vcpu, wi, wr);
- if (wi->ha)
- new_desc |= PTE_AF;
-
- if (new_desc != ws.desc) {
- if (wi->s2 && !ws.s2_trans.writable) {
- fail_s1_walk(wr, ESR_ELx_FSC_PERM_L(ws.level), true);
- return -EPERM;
- }
-
- ret = kvm_swap_s1_desc(vcpu, ws.desc_pa, ws.desc, new_desc, wi);
- if (ret == -EAGAIN)
- return ret;
- if (ret) {
- fail_s1_walk(wr, ESR_ELx_FSC_SEA_TTW(ws.level), false);
- return ret;
- }
-
- ws.desc = new_desc;
- }
+ ret = handle_desc_update(vcpu, wi, &ws, wr, access);
+ if (ret)
+ return ret;
if (!(ws.desc & PTE_AF)) {
fail_s1_walk(wr, ESR_ELx_FSC_ACCESS_L(ws.level), false);
--
2.47.3
next prev parent reply other threads:[~2026-10-23 20:56 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-23 20:55 [PATCH v2 00/28] KVM: arm64: nv: Implement FEAT_HAFDBS, FEAT_HAFT Oliver Upton
2026-10-23 20:55 ` [PATCH v2 01/28] KVM: arm64: nv: Introduce struct for stage-2 walk step Oliver Upton
2026-10-23 20:55 ` [PATCH v2 02/28] KVM: arm64: nv: Consolidate computation of stage-2 permissions Oliver Upton
2026-10-23 20:55 ` [PATCH v2 03/28] KVM: arm64: nv: Get rid of kvm_s2_trans*() accessors Oliver Upton
2026-10-23 20:55 ` [PATCH v2 04/28] KVM: arm64: nv: Only shadow writable-dirty guest descs as writable Oliver Upton
2026-10-23 21:25 ` sashiko-bot
2026-10-24 6:26 ` Oliver Upton
2026-10-23 20:55 ` [PATCH v2 05/28] KVM: arm64: nv: Pass an access descriptor for stage-2 walks Oliver Upton
2026-10-23 20:55 ` [PATCH v2 06/28] KVM: arm64: nv: Use a helper for stage-2 descriptor updates Oliver Upton
2026-10-23 20:55 ` [PATCH v2 07/28] KVM: arm64: nv: Set dirty state at stage-2 Oliver Upton
2026-10-23 20:55 ` [PATCH v2 08/28] KVM: arm64: nv: Treat DBM as writable " Oliver Upton
2026-10-23 20:55 ` [PATCH v2 09/28] KVM: arm64: Compute S1 permissions as part of s1_walk() Oliver Upton
2026-10-23 20:55 ` [PATCH v2 10/28] KVM: arm64: Plumb through access descriptor for stage-1 Oliver Upton
2026-10-23 21:06 ` sashiko-bot
2026-10-23 20:55 ` [PATCH v2 11/28] KVM: arm64: Use a struct for stage-1 walk context Oliver Upton
2026-10-23 20:55 ` Oliver Upton [this message]
2026-10-23 20:55 ` [PATCH v2 13/28] KVM: arm64: Set dirty state at stage-1 Oliver Upton
2026-10-23 20:55 ` [PATCH v2 14/28] KVM: arm64: nv: Respect HA when computing translated TCR Oliver Upton
2026-10-23 20:55 ` [PATCH v2 15/28] KVM: arm64: nv: Respect HD " Oliver Upton
2026-10-23 20:55 ` [PATCH v2 16/28] KVM: arm64: Grant write permission when DBM is set at S1 Oliver Upton
2026-10-23 20:55 ` [PATCH v2 17/28] KVM: arm64: Don't update descriptors for "non-arch" access Oliver Upton
2026-10-23 20:56 ` [PATCH v2 18/28] KVM: arm64: nv: Emulate CMOs via writable-clean translations as NOPs Oliver Upton
2026-10-23 20:56 ` [PATCH v2 19/28] arm64: Add command line switch to disable FEAT_S2FWB Oliver Upton
2026-10-23 20:56 ` [PATCH v2 20/28] KVM: arm64: Reject non-coherent DMA when using forced writeback Oliver Upton
2026-10-23 21:16 ` sashiko-bot
2026-10-23 20:56 ` [PATCH v2 21/28] KVM: arm64: nv: Expose FEAT_HAFDBS Oliver Upton
2026-10-23 20:56 ` [PATCH v2 22/28] KVM: arm64: Set Access flag on table descriptors at stage-1 Oliver Upton
2026-10-23 21:22 ` sashiko-bot
2026-10-24 6:24 ` Oliver Upton
2026-10-23 20:56 ` [PATCH v2 23/28] KVM: arm64: nv: Set access flag on table descriptors at stage-2 Oliver Upton
2026-10-23 20:56 ` [PATCH v2 24/28] KVM: arm64: nv: Expose FEAT_HAFT Oliver Upton
2026-10-23 20:56 ` [PATCH v2 25/28] KVM: arm64: selftests: Only test AF behavior for emulated AT insns Oliver Upton
2026-10-23 20:56 ` [PATCH v2 26/28] KVM: arm64: selftests: Test AT emulation for FEAT_HAFT Oliver Upton
2026-10-23 20:56 ` [PATCH v2 27/28] KVM: arm64: Add tracepoints for S1 page table walk Oliver Upton
2026-10-23 20:56 ` [PATCH v2 28/28] KVM: arm64: Add tracepoints for S2 " Oliver Upton
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