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Message-ID: <9df7db0e-649f-4d19-b1bc-c1919d3d8c4c@redhat.com> Date: Fri, 6 Sep 2024 14:52:12 +1000 From: Gavin Shan <gshan@...hat.com> To: Steven Price <steven.price@....com>, kvm@...r.kernel.org, kvmarm@...ts.linux.dev Cc: Catalin Marinas <catalin.marinas@....com>, Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>, James Morse <james.morse@....com>, Oliver Upton <oliver.upton@...ux.dev>, Suzuki K Poulose <suzuki.poulose@....com>, Zenghui Yu <yuzenghui@...wei.com>, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, Joey Gouly <joey.gouly@....com>, Alexandru Elisei <alexandru.elisei@....com>, Christoffer Dall <christoffer.dall@....com>, Fuad Tabba <tabba@...gle.com>, linux-coco@...ts.linux.dev, Ganapatrao Kulkarni <gankulkarni@...amperecomputing.com>, Shanker Donthineni <sdonthineni@...dia.com>, Alper Gun <alpergun@...gle.com> Subject: Re: [PATCH v5 07/19] arm64: rsi: Add support for checking whether an MMIO is protected On 9/6/24 2:32 PM, Gavin Shan wrote: > On 8/19/24 11:19 PM, Steven Price wrote: >> From: Suzuki K Poulose <suzuki.poulose@....com> >> >> On Arm CCA, with RMM-v1.0, all MMIO regions are shared. However, in >> the future, an Arm CCA-v1.0 compliant guest may be run in a lesser >> privileged partition in the Realm World (with Arm CCA-v1.1 Planes >> feature). In this case, some of the MMIO regions may be emulated >> by a higher privileged component in the Realm world, i.e, protected. >> >> Thus the guest must decide today, whether a given MMIO region is shared >> vs Protected and create the stage1 mapping accordingly. On Arm CCA, this >> detection is based on the "IPA State" (RIPAS == RIPAS_IO). Provide a >> helper to run this check on a given range of MMIO. >> >> Also, provide a arm64 helper which may be hooked in by other solutions. >> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com> >> Signed-off-by: Steven Price <steven.price@....com> >> --- >> New patch for v5 >> --- >> arch/arm64/include/asm/io.h | 8 ++++++++ >> arch/arm64/include/asm/rsi.h | 3 +++ >> arch/arm64/include/asm/rsi_cmds.h | 21 +++++++++++++++++++++ >> arch/arm64/kernel/rsi.c | 26 ++++++++++++++++++++++++++ >> 4 files changed, 58 insertions(+) >> >> diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h >> index 1ada23a6ec19..a6c551c5e44e 100644 >> --- a/arch/arm64/include/asm/io.h >> +++ b/arch/arm64/include/asm/io.h >> @@ -17,6 +17,7 @@ >> #include <asm/early_ioremap.h> >> #include <asm/alternative.h> >> #include <asm/cpufeature.h> >> +#include <asm/rsi.h> >> /* >> * Generic IO read/write. These perform native-endian accesses. >> @@ -318,4 +319,11 @@ extern bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size, >> unsigned long flags); >> #define arch_memremap_can_ram_remap arch_memremap_can_ram_remap >> +static inline bool arm64_is_iomem_private(phys_addr_t phys_addr, size_t size) >> +{ >> + if (unlikely(is_realm_world())) >> + return arm64_rsi_is_protected_mmio(phys_addr, size); >> + return false; >> +} >> + >> #endif /* __ASM_IO_H */ >> diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h >> index 2bc013badbc3..e31231b50b6a 100644 >> --- a/arch/arm64/include/asm/rsi.h >> +++ b/arch/arm64/include/asm/rsi.h >> @@ -13,6 +13,9 @@ DECLARE_STATIC_KEY_FALSE(rsi_present); >> void __init arm64_rsi_init(void); >> void __init arm64_rsi_setup_memory(void); >> + >> +bool arm64_rsi_is_protected_mmio(phys_addr_t base, size_t size); >> + >> static inline bool is_realm_world(void) >> { >> return static_branch_unlikely(&rsi_present); >> diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h >> index 968b03f4e703..c2363f36d167 100644 >> --- a/arch/arm64/include/asm/rsi_cmds.h >> +++ b/arch/arm64/include/asm/rsi_cmds.h >> @@ -45,6 +45,27 @@ static inline unsigned long rsi_get_realm_config(struct realm_config *cfg) >> return res.a0; >> } >> +static inline unsigned long rsi_ipa_state_get(phys_addr_t start, >> + phys_addr_t end, >> + enum ripas *state, >> + phys_addr_t *top) >> +{ >> + struct arm_smccc_res res; >> + >> + arm_smccc_smc(SMC_RSI_IPA_STATE_GET, >> + start, end, 0, 0, 0, 0, 0, >> + &res); >> + >> + if (res.a0 == RSI_SUCCESS) { >> + if (top) >> + *top = res.a1; >> + if (state) >> + *state = res.a2; >> + } >> + >> + return res.a0; >> +} >> + >> static inline unsigned long rsi_set_addr_range_state(phys_addr_t start, >> phys_addr_t end, >> enum ripas state, >> diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c >> index e968a5c9929e..381a5b9a5333 100644 >> --- a/arch/arm64/kernel/rsi.c >> +++ b/arch/arm64/kernel/rsi.c >> @@ -67,6 +67,32 @@ void __init arm64_rsi_setup_memory(void) >> } >> } >> +bool arm64_rsi_is_protected_mmio(phys_addr_t base, size_t size) >> +{ >> + enum ripas ripas; >> + phys_addr_t end, top; >> + >> + /* Overflow ? */ >> + if (WARN_ON(base + size < base)) >> + return false; >> + >> + end = ALIGN(base + size, RSI_GRANULE_SIZE); >> + base = ALIGN_DOWN(base, RSI_GRANULE_SIZE); >> + >> + while (base < end) { >> + if (WARN_ON(rsi_ipa_state_get(base, end, &ripas, &top))) >> + break; >> + if (WARN_ON(top <= base)) >> + break; >> + if (ripas != RSI_RIPAS_IO) >> + break; >> + base = top; >> + } >> + >> + return (size && base >= end); >> +} > > The unexpected calltrace is continuously observed with host/v4, guest/v5 and > latest upstream tf-rmm on 'WARN_ON(top <= base)' because @top is never updated > by the latest tf-rmm. The following call path indicates how SMC_RSI_IPA_STATE_GET > is handled by tf-rmm. I don't see RSI_RIPAS_IO is defined there and @top is > updated. > > [ 0.000000] ------------[ cut here ]------------ > [ 0.000000] WARNING: CPU: 0 PID: 0 at arch/arm64/kernel/rsi.c:103 arm64_rsi_is_protected_mmio+0xf0/0x110 > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.11.0-rc1-gavin-g3527d001084e #1 > [ 0.000000] Hardware name: linux,dummy-virt (DT) > [ 0.000000] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [ 0.000000] pc : arm64_rsi_is_protected_mmio+0xf0/0x110 > [ 0.000000] lr : arm64_rsi_is_protected_mmio+0x80/0x110 > [ 0.000000] sp : ffffcd7097053bf0 > [ 0.000000] x29: ffffcd7097053c30 x28: 0000000000000000 x27: 0000000000000000 > [ 0.000000] x26: 00000000000003d0 x25: 00000000ffffff8e x24: ffffcd7096831bd0 > [ 0.000000] x23: ffffcd7097053c08 x22: 00000000c4000198 x21: 0000000000001000 > [ 0.000000] x20: 0000000001001000 x19: 0000000001000000 x18: 0000000000000002 > [ 0.000000] x17: 0000000000000000 x16: 0000000000000010 x15: 0001000080000000 > [ 0.000000] x14: 0068000000000703 x13: ffffffffff5fe000 x12: ffffcd7097053ba4 > [ 0.000000] x11: 00000000000003d0 x10: ffffcd7097053bc4 x9 : 0000000000000444 > [ 0.000000] x8 : ffffffffff5fe000 x7 : 0000000000000000 x6 : 0000000000000000 > [ 0.000000] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 > [ 0.000000] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 > [ 0.000000] Call trace: > [ 0.000000] arm64_rsi_is_protected_mmio+0xf0/0x110 > [ 0.000000] set_fixmap_io+0x8c/0xd0 > [ 0.000000] of_setup_earlycon+0xa0/0x294 > [ 0.000000] early_init_dt_scan_chosen_stdout+0x104/0x1dc > [ 0.000000] acpi_boot_table_init+0x1a4/0x2d8 > [ 0.000000] setup_arch+0x240/0x610 > [ 0.000000] start_kernel+0x6c/0x708 > [ 0.000000] __primary_switched+0x80/0x88 > I have local changes like below to avoid the unexpected calltrace. diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c index 9cb3353e5cbf..3d132d45fd83 100644 --- a/arch/arm64/kernel/rsi.c +++ b/arch/arm64/kernel/rsi.c @@ -100,14 +100,15 @@ bool arm64_rsi_is_protected_mmio(phys_addr_t base, size_t size) while (base < end) { if (WARN_ON(rsi_ipa_state_get(base, end, &ripas, &top))) break; - if (WARN_ON(top <= base)) + if (WARN_ON(top && top <= base)) break; if (ripas != RSI_RIPAS_IO) break; - base = top; + + base = top ? top : end; } - return (size && base >= end); + return base >= end; Thanks, Gavin
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