Date: Tue, 23 Sep 2025 17:09:32 GMT From: Andrew Turner <andrew@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 0f455824d0ab - main - arm64/vmm: Add a feature flag and use it for HCRX Message-ID: <202509231709.58NH9WAd077214@gitrepo.freebsd.org>
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The branch main has been updated by andrew: URL: https://cgit.FreeBSD.org/src/commit/?id=0f455824d0abdcf09d2e96cf97f99c542bbde877 commit 0f455824d0abdcf09d2e96cf97f99c542bbde877 Author: Andrew Turner <andrew@FreeBSD.org> AuthorDate: 2025-09-22 17:07:57 +0000 Commit: Andrew Turner <andrew@FreeBSD.org> CommitDate: 2025-09-23 17:08:36 +0000 arm64/vmm: Add a feature flag and use it for HCRX Add a field to hold the features the hardware supports that need to be handled when switching to a guest and use it to handle FEAT_HCX that adds the HRX_EL2 register. This reduces the number of times we read ID registers in guest switching which may be trapped when running under nested virtualisation. Sponsored by: Arm Ltd Differential Revision: https://reviews.freebsd.org/D51816 --- sys/arm64/vmm/arm64.h | 2 ++ sys/arm64/vmm/vmm_arm64.c | 6 ++++++ sys/arm64/vmm/vmm_hyp.c | 28 +++++++++++++++------------- 3 files changed, 23 insertions(+), 13 deletions(-) diff --git a/sys/arm64/vmm/arm64.h b/sys/arm64/vmm/arm64.h index 6a0c4c78e568..0bd5a933bee1 100644 --- a/sys/arm64/vmm/arm64.h +++ b/sys/arm64/vmm/arm64.h @@ -125,6 +125,8 @@ struct hyp { uint64_t vmid_generation; uint64_t vttbr_el2; uint64_t el2_addr; /* The address of this in el2 space */ + uint64_t feats; /* Which features are enabled */ +#define HYP_FEAT_HCX (0x1ul << 0) bool vgic_attached; struct vgic_v3 *vgic; struct hypctx *ctx[]; diff --git a/sys/arm64/vmm/vmm_arm64.c b/sys/arm64/vmm/vmm_arm64.c index e293c99a6646..70bb914d68c6 100644 --- a/sys/arm64/vmm/vmm_arm64.c +++ b/sys/arm64/vmm/vmm_arm64.c @@ -517,6 +517,7 @@ vmmops_init(struct vm *vm, pmap_t pmap) { struct hyp *hyp; vm_size_t size; + uint64_t idreg; size = el2_hyp_size(vm); hyp = malloc_aligned(size, PAGE_SIZE, M_HYP, M_WAITOK | M_ZERO); @@ -524,6 +525,11 @@ vmmops_init(struct vm *vm, pmap_t pmap) hyp->vm = vm; hyp->vgic_attached = false; + if (get_kernel_reg(ID_AA64MMFR1_EL1, &idreg)) { + if (ID_AA64MMFR1_HCX_VAL(idreg) >= ID_AA64MMFR1_HCX_IMPL) + hyp->feats |= HYP_FEAT_HCX; + } + vtimer_vminit(hyp); vgic_vminit(hyp); diff --git a/sys/arm64/vmm/vmm_hyp.c b/sys/arm64/vmm/vmm_hyp.c index d61885c15871..475ad79f63cc 100644 --- a/sys/arm64/vmm/vmm_hyp.c +++ b/sys/arm64/vmm/vmm_hyp.c @@ -259,14 +259,6 @@ vmm_hyp_reg_store(struct hypctx *hypctx, struct hyp *hyp, bool guest) hypctx->hcr_el2 = READ_SPECIALREG(hcr_el2); hypctx->vpidr_el2 = READ_SPECIALREG(vpidr_el2); hypctx->vmpidr_el2 = READ_SPECIALREG(vmpidr_el2); - -#ifndef VMM_VHE - /* hcrx_el2 depends on feat_hcx */ - uint64_t mmfr1 = READ_SPECIALREG(id_aa64mmfr1_el1); - if (ID_AA64MMFR1_HCX_VAL(mmfr1) >> ID_AA64MMFR1_HCX_SHIFT) { - hypctx->hcrx_el2 = READ_SPECIALREG(MRS_REG_ALT_NAME(HCRX_EL2)); - } -#endif } static void @@ -277,11 +269,9 @@ vmm_hyp_reg_restore(struct hypctx *hypctx, struct hyp *hyp, bool guest) /* Restore the special registers */ WRITE_SPECIALREG(hcr_el2, hypctx->hcr_el2); - if (guest_or_nonvhe(guest)) { - uint64_t mmfr1 = READ_SPECIALREG(id_aa64mmfr1_el1); - if (ID_AA64MMFR1_HCX_VAL(mmfr1) >> ID_AA64MMFR1_HCX_SHIFT) { - WRITE_SPECIALREG(MRS_REG_ALT_NAME(HCRX_EL2), hypctx->hcrx_el2); - } + if (guest) { + if ((hyp->feats & HYP_FEAT_HCX) != 0) + WRITE_SPECIALREG(HCRX_EL2_REG, hypctx->hcrx_el2); } isb(); @@ -502,11 +492,18 @@ vmm_hyp_call_guest(struct hyp *hyp, struct hypctx *hypctx) struct hypctx host_hypctx; uint64_t cntvoff_el2; uint64_t ich_hcr_el2, ich_vmcr_el2, cnthctl_el2, cntkctl_el1; +#ifndef VMM_VHE + uint64_t hcrx_el2; +#endif uint64_t ret; uint64_t s1e1r, hpfar_el2; bool hpfar_valid; vmm_hyp_reg_store(&host_hypctx, NULL, false); +#ifndef VMM_VHE + if ((hyp->feats & HYP_FEAT_HCX) != 0) + hcrx_el2 = READ_SPECIALREG(MRS_REG_ALT_NAME(HCRX_EL2)); +#endif /* Save the host special registers */ cnthctl_el2 = READ_SPECIALREG(cnthctl_el2); @@ -584,6 +581,11 @@ vmm_hyp_call_guest(struct hyp *hyp, struct hypctx *hypctx) vmm_hyp_reg_restore(&host_hypctx, NULL, false); +#ifndef VMM_VHE + if ((hyp->feats & HYP_FEAT_HCX) != 0) + WRITE_SPECIALREG(MRS_REG_ALT_NAME(HCRX_EL2), hcrx_el2); +#endif + /* Restore the host special registers */ WRITE_SPECIALREG(ich_hcr_el2, ich_hcr_el2); WRITE_SPECIALREG(ich_vmcr_el2, ich_vmcr_el2);
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